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REESE   LIBRARY 

OF  THE 

UNIVERSITY  OF  CALIFORNIA. 

MAR  23.1894     ..:,  -t89   . 
Class  No.. 


STREET  RAILWAY  MOTORS. 


STREET  RAILWAY  MOTORS: 


WITH 


DESCRIPTIONS  AND  COST  OF  PLANTS  AND 

OPERATION  OF  THE  VARIOUS 

SYSTEMS  IN  USE 


OB  PROPOSED  FOR 


MOTIVE  POWER  ON  STREET  RAILWAYS. 


BY 

HERMAN  HAUPT,  C.  E. 

CHIEF  OP  BUREAU  OF  MILITARY  RAILROADS  DURING  THE  LATE  WAR  ;  LATE  CHIEF 

ENGINEER  PENNSYLVANIA  R.  R.  ;  GENERAL  MANAGER  NORTHERN   PACIFIC 

R.  R. ;  PIEDMONT  AIR  LINE  ;  CHIEF  ENGINEER  TIDE  WATER  PIPE  LINE. 


fc 
JNJVEKSIT1 


PHILADELPHIA: 
HENRY   CAREY    BAIRD    &    CO. 

INDUSTRIAL  PUBLISHERS,  BOOKSELLERS  AND  IMPORTERS, 
810  WALNUT  STREET. 

LONDON:    E.   &    F.   N.   SPON, 

125  STRAND. 

1893. 


BY 

HERMAN    HAUPT. 
1893. 


PRINTED  AT  THE  COLLINS  PRINTING  HOUSE, 

705  Jayne  Street, 
PHILADELPHIA,  U.  S.  A. 


PREFACE. 


THE  present  age  seems  to  be  peculiarly  prolific  in 
the  invention  of  motors  for  street  railways  and  in  new 
applications  of  old  and  recognized  motor  forces  for 
propulsion  of  the  cars  used  for  urban  and  suburban 
transit.  Some  of  these  possess  decided  merits,  and 
present  claims  for  the  support  of  capitalists  and  of  the 
public  that  are,  at  least,  worthy  of  careful  examination ; 
others  are  advanced  by  parties  who  are  evidently  igno- 
rant of  the  ther mo-dynamic,  chemical,  and  mechanical 
laws  upon  which  some  of  these  operations  depend,  and 
schemes  are  sometimes  presented  that  are  visionary  and 
impracticable.  A  brief  review  of  the  plans  proposed 
for  street  railways,  their  merits  and  defects,  with  the 
cost  of  plant  and  of  operation,  will  probably  possess 
sufficient  interest  at  the  present  time  to  excuse  the 
preparation  and  publication  of  this  volume. 

The  aim  of  the  writer  has  not  been  to  furnish  an 
elaborate  treatise  requiring  for  its  comprehension  a  high 
degree  of  technical  knowledge,  but  rather  a  simple  state- 
ment of  principles  and  their  applications  that  will  be 


VI  PREFACE. 

readily  comprehended  by  persons  of  limited  scientific 
attainments — a  treatise  for  the  use  and  information  of 
investors  and  of  the  public. 

The  subjects  here  considered  are  horse  railroads, 
steam  motors,  cable  traction,  electric  roads,  com- 
pressed-air motors,  ammonia  motors,  hot-water  motors, 
gas  motors,  and  carbonic-acid  motors. 

It  is  not  proposed  to  attempt  any  details  of  mechani- 
cal construction  or  furnish  illustrations.  This  ground 
has  been  fully  covered  by  several  volumes  already 
published.  The  object  is  simply  to  give  results,  with 
such  simple  explanations  of  principles  as  will  be  of 
interest  and  be  intelligible  to  practical  men  who  may  be 
called  upon  to  contribute  capital  for  construction  or 
use  their  votes  or  influence  in  favor  of  any  proposed 
system  of  rapid  or  local  transit  in  cities. 

PHILADELPHIA,  March  25,  1893. 


ADDRESS. 

As  frequent  inquiries  are  made  for  the  address  of  the  author, 
it  may  be  well  to  state  that  his  permanent  summer  residence  is  at 
St.  Paul,  Minn. 

Communications  may  be  addressed  as  follows : 

H.  HAUPT,  593  Holly  Avenue, 

St.  Paul,  Minn. 

or  care  of  L.  M.  HAUPT,  107  N.  35th  St., 

Philadelphia,  Pa. 


CONTENTS. 


I.     HORSE  RAILWAYS. 

PAGE 

Cost  of  plant,  Second  Avenue  Railroad       .         .         .         .  1 

Expenses  of  operation         .         .         .         .         .         .         .  2 

Other  expenses ;  Car-mile  expenses  .  .'  .  .  •  '  3 
Operating  expenses  of  sixteen  companies;  Data  given  by 

Charles  H.  Davis    .         .'        .'        .'.•/.         .  4 

Data  from  census  bulletin  »         ......  •    •  4.        .         .  5 

Data  from  West  End  Company;  Statement  of  Mr.  H.  H. 

Windsor 6 

Cost  of  horse-power  .  .  .  .  .....  7 

II.     STEAM  MOTORS. 

Properties  and  composition  of  water   .....         8 
Thermornetrical  and  other  units  ;   Specific  heat    ...         9 
Air  required  for  combustion ;  Thermal  units  and  evapora- 
tion          10 

Evaporation  in  locomotives  ;   Consumption  of  coal  per  square 

foot  of  grate 11 

Consumption  of  steam  per  horse-power;   Horse-power  re- 
quired to  propel  a  street  motor         .          .         .         -.          .12 
Consumption   of  coal  per  mile  run ;    Cost  and  number  of 
motors  required       .          .         .         .          .          .          .         .13 

Repairs  and  depreciation  of  motors     .         .         .  15 

Plant  required  for  six  miles  of  double  track  .  .  .16 
Cost  of  operation  of  six  miles  of  double  track  .  .  .17 


Vlll  CONTENTS. 

III.     AMMONIA  MOTOR. 

PAGE 

Properties  of  ammonia         .          .         .          .         .         .         .17 

Ammonia  motor  of  Dr.  Emile  Lamm ;   Force  dependent  on 
heat,  not  on  element  employed        .         .         .         .         .19 

Power  from  ammonia  capable  of  subdivision        ...       20 
Boiling-point  of  fluid  unimportant  in  production  of  power    .        21 
Ammonia  engine  abandoned  by   Dr.  Lamm ;    Reasons  for 

abandonment  given  by  General  Beauregard      .         .          .22 
Description  of  Lamm's  ammonia  engine     .          .          .         .23 

Tests  by  General  Beauregard  ;   Cost  and  time  of  distillation       24 
Estimate  of  cost  of  operation  by  committee ;  Observations 
on  estimate  of  committee          ......       25 

Second  estimate  on  different  basis  ;    Revival  of  ammonia 

motor  in  New  York 26 

Dimensions  of  New  York  motor  ;  Claims  of  New  York  com- 
pany      .         .         .          .          .         .  .         .         .27 

IV.     THE  HOT-WATER  MOTOR. 

Otherwise  designated  fireless  locomotive ;    Upon  what  the 
efficacy  depends      ........       28 

Table  of  temperatures  and  pressures ;    Sum  of  latent  and 
sensible  heat  not  constant         .          .          .  .         .29 

Water  cooled  by  conversion  of  a  portion  into  steam     .          .       30 
Table  of  temperatures,    pressures,    volumes,    and    thermal 
units;  Illustration  of  use  of  table    .          .         .          .          .31 

Description  of,  dimensions  and  operation  of  fireless  locomotive       32 
Explanation  of  difficulty  in  operation ;  Test  of  another  hot- 
water  motor    .........       33 

The  term  fireless  inappropriate  .         .         .         ,         .         .34 
Extent  to  which  water  is  cooled  by  evaporation  ...       35 
Possible  length  of  run  of  motor  by  hot  water  alone  ;  Cost  of 
plant  and  of  operation  of  ammonia  and  hot-water  motors       36 

V.     GAS  MOTORS. 

Distinction  between  gas  and  other  motors    .         .         .         .37 
Thermal  units  utilized  in  steam  and  gas  engines  ;  Increased 
efficiency  from  direct  application      .         .         .         .         .38 


CONTENTS.  IX 

PAGE 

Twenty  gas  motors  ordered  in  Chicago ;  Description  of  the 

Connelly  gas  motor          .",..•'*._        .          .          .          .  39 

Cost  of  operation  of  Connelly  motor  ;  Two  forms  of  motor 
proposed,  and  cost  .         ".         .         .         .         .         .41 

Remarks  on  gas  motors       ~.         '.    ,     ,          .  ^     .          .          .  42 

Consumption  and  cost  of  fuel      .         •  '.'..•         .         .         .  43 

Continuous  motion  of  machinery  required  ....  44 

VI.     THE  PNEUMATIC  on  COMPRESSED  AIR  MOTOR. 

Reference  to  investigation  in  1879 44 

Cost  of  compressed  air  one-fourth  that  of  steam  in  motors  ; 
Air  the  cheapest  power  for  street  railways  ;  Can  be  trans- 
mitted without  serious  loss       .         .         .          .          .          .45 

Properties  of  air          .         ,         .         .          .          .          .          .       46 

Isothermal  and  adiabatic  compression  ;   Heat  lost  is  less  at 
high  than  at  low  pressure         .          .          .         .         .          .47 

Increase  of  temperature  with  adiabatic  compression      .         .       48 
Improvements  in  air  compressors ;  Loss  of  pressure  by  trans- 
mission through  pipes  ;   Use  of  compressed  air  in  France, 
England,  and  Germany  .          .         .          ...          .       49 

Percentage  of  efficiency  obtained ;    Cubic   feet  of  air   per 
horse-power  ;   Coal  required  for  reheating  in  Paris  ;   Rule 
by  which  to  estimate  loss  of  pressure  in  transmission  of  air       50 
Initial  density  not  to  be  considered  ;  Cost  of  hydraulic  pipes       51 
Quantity  of  free  air  required  for  street  motors     .         .         .       52 
Capacity  of  reservoir  .          .         .          .         .         .         .       53 

High  pressures  useful  only  for  increase  of  storage  capacity  ; 

Loss  in  coal  from  high  compression,  one  mill  per  mile       .       54 
Increase  of  work  possible  if  high  pressure  could  be  utilized  ; 
Loss  of  power  by  wire  drawing        .....       56 

Hardie's  tests  with  high  pressures        .         .         .          .         .57 

Beaumont's  tests  with  high  pressures  ....       58 

Beaumont's  table  of  experimental  data        ....       59 

Discussion  of  Beaumont's  tests;  Advantages  of  cylinder  ex- 
pansion beyond  certain  limits  only  theoretical  .         .         .       60 


X  CONTENTS. 

VII.     TESTS  OF  THE  HARDIE  COMPRESSED  AIR  MOTOR. 

PAGE 

Five  motors  run  on  Second  Avenue  Railroad,  New  York  ; 

Motors  designed  by  Robert  Hardie  .  .  .  .61' 

Observations  in  regard  to  air  compression    .         .          .         .62 

No  loss  in  compressing  air  measured  by  cost  of  power          .       63 

Coal  required  for  one  horse-power  in  air  compression  ;  Cost 
of  compressed  air  one- fourth  that  of  steam  for  motors  .  64 

Pressure  of  air  in  car  reservoirs ;  Pressure  at  which  air  is 
used  in  motor  cylinders  ;  Air  heated  before  admitted  to 
cylinders  ;  Increase  in  volume  of  dry  air  by  heating  .  65 

Additional  increase  in  volume  from  moisture  ;  Proof  that 
power  is  doubled  by  heating  air  ;  Reducing  valve  .  .  66 

Cost  per  mile  of  heating  the  air  ;  Miles  run  by  the  pneumatic 
motor  .  .  ...  .  .  67 

Actual  performance  in  excess  of  theoretical  limits  ;  Explana- 
tion found  in  use  of  suction  valves  ;  Cylinders  acting  as  air 
pumps  and  brakes  ........  68 

Quantity  of  air  restored  on  down  grades  ;  H  eat  and  cold  by 
compression  and  expansion 70 

Description  of  Delamater  air  compressors  ;  Air  cooled  by 
water-tanks;  Air  dried  by  passing  through  water  .  .  71 

Frost  formed  at  low  pressures  only ;  Suggestion  in  regard 
to  use  of  air  for  power  .......  72 

Effect  of  rupture  of  air  cylinder ;  Grades  overcome  by 
motors;  Power  of  motor  cylinders  ....  73 

Traction  of  trains        ........        75 

Traction  of  motors,  twenty-five  pounds  per  ton  ;   Grades      .        76 

Power  of  motor  with  full  cylinder  of  air ;  Small  five-ton  in- 
dependent motors 77 

Traction  of  trail  cars  .         .         .         .         .         .         .78 

Reservoirs  of  air  in  trail  cars  ;  Application  of  air  motors  to 
elevated  railroads ;  Power  to  replace  motors  when  de- 
railed .  .  .  .  .  .  .  .  .79 

Horse-power  of  the  Hardie  motor  ;  Minor  points  in  favor  of 
air  motor  .........  80 

Objections  considered          .         .         .         .         .         .         .81 

Location  of  power  plant ;   Use  and  distribution  of  reservoirs       83 


CONTENTS.  XI 

PAGE 

Location  of  compressor  plant  on  extended  lines  ;  Use  of  in- 
termediate reservoirs ;  Operation  of  ordinary  railroads  by 

compressed  air        .  '  ^     *  ..        ....  8f> 

Direct  experiments  with  the  Hardie,  motor  ...  86 

Discussion  of  results  of  tests       .     ''.-••".•    -••••'     ...  89 

Loss  of  thermal  units  in  tank  by  heating  air        ...  92 
Suggestion  for  use  of  petroleum  stove  for  reheating  ;  Hardie's 

estimate  of  cost  of  reheating    ......  93 

Increase  of  power  by  steam  from  reheating  tank  .         .  94 

VIII.     ECONOMICAL  MODES  OF  COMPRESSION. 

Statement  of  Mr.  E.  Hill,  of  Norwalk  Iron  Company         .       94 
Horse-power  required  for  compression          .         .         .  96 

Frost  from  expansion  of  air         .         .          .         .          .          .97 

Less  frost  from  high  than  from  low  pressure         .        '.         .98 
Explanation  of  observed  facts  ;  General  ignorance  in  regard 
to  the  use  of  compressed  air    .         .         .  .         .99 

IX.    COST  OF  OPERATION  OF  THE  COMPRESSED  AIR  MOTOR 
FOR  ONE  DAY — Six  MILES  DOUBLE  TRACK. 

Data  given          .         .         .         .         .         .         .         .         .100 

Cost  of  plant  for  six  miles  of  double  track ;  Cost  of  street 
construction  ;  Cost  of  equipment ;  Summary  of  cost  of 

plant 101 

Cost  of  operation;  Compressed  air  for  elevated  railroads; 
Elevated  railroad  motor  constructed  by  the  Baldwin  Com- 
pany  102 

Report  of  tests  on  elevated  railroad,  by  Charles  W.  Potter  .     103 

Quantity  of  free  air  required 104 

Storage  pressure  and  horse-power  required  .         .         .105 

Average  coal  consumption  in  the  steam  motors  used  ;  Saving 

in  cost  of  labor  ;  Saving  in  cost  of  fuel     ....     106 
Cost  of  compressor  plant ;   Why  compressed  air  is  not  in 
general  use      .........     107 

Mr.  Hardie's  explanation  of  causes 108 

New  plans  prepared Ill 


XI 1  CONTENTS. 

X.     OTHER  AIR  MOTORS. 

PAGE 

Some  of  them   misnamed — not   really  air  motors ;    Power 
communicated  by  rotating  pipe         .          .         .          .          .111 

Atmospheric  railway  a  failure 112 

A  new  motor  on  similar  principle  proposed  .         .          .113 

XI.     CABLE  AND  ELECTRIC  ROADS. 

Comparisons  difficult  from  unreliable  data   .         .  .  .114 

Data  assumed  as  basis  of  comparison  .          .         .  .  .115 

Extracts  from  various  sources  of  cost  of  operation  .  .116 

Estimates  of  cost  from  uniform  data    .          .          .  .  .121 

Cost  of  plant  and  of  operation  of  horse  railroads  .  .122 
Cable  roads,  notes  on,  from  Fairchild's  "  Street  Railways"  123 

Rules  for  estimating  power  at  central  station        .  .  .124 

Cost  of  plant  and  of  operation  of  cable  road          .  .  .125 

XII.     ELECTRIC  LINES. 

Table  of  horse-power  required  at  axles  .  .  .  .128 
Electric  traction  efficiency  ;  Cost  of  items  in  electric  railroad 

construction  and  equipment     .         .         .         .         .         .129 

Cost  of  power  on  electric  lines ;  Summary  of  expenses,  by 

Crosby  and  Hall 130 

Expenses  of  the  West  End  Railroad,  Boston  ;  Cost  of  plant 

and  of  operation  of  electric  railroads  ....  131 
General  summary ;  Cost  of  plant  and  of  operation  of  six 

miles  by  horse-power  .  .  .  ;-.-..  .  .133 
Cost  of  plant  and  of  operation  of  six  miles  by  steam ;  Cost 

of  plant  and  of  operation  of  six  miles  by  ammonia  .  .134 
By  hot  water ;  Cost  of  plant  and  of  operation  of  six  miles 

by  gas  motors  --....••• ,».-..  135 

By  compressed  air  .  .  .  .  .  ji:  ..  ...  136 
Cost  of  plant  and  of  operation  of  six  miles  by  cable  and  by 

electric  lines    .         .         .         ...        ....        .         .137 


CONTENTS.  Xlll 

XIII.     LOW-PRESSURE  AIR  MOTORS. 

PAGE 

Objection  to  cable  and  electric  lines  ;   Carbonic  acid  motor  .     139 

XIV.     STORAGE  BATTERIES. 

Conditions  required  in  a  perfect  motor          .         .         .         .141 

Comparison  of  motors — table  of  relative  cost  of  operation 

and  of  plant ;  Remarks  on  the  ammonia  motor         .         .  142 

Horse-power;  Compressed  air    ......  143 

Gas  motors         .........  144 

Steam  and  hot- water  motors  ;   Electric  lines  ;  Cable  lines     .  145 

The  aim  in  reviewing  the  various  street  railway  systems       .  146 

XV.  COST  OF  CARBONIC  ACID  AS  A  MOTIVE  POWER. 

Cost  of  carbonic  acid,  as  stated  in  an  article  in  the  New 
York  World ;  Over-estimation  of  the  power  of  carbonic 
acid;  Cost  of  sulphuric  acid  .  .  .*  .  .  .  147 

The  highest  pressure  at  which  steam,  air,  or  gas  can  be  used 
to  advantage  upon  the  piston  of  an  engine  ;  Thermal  units 
developed  by  one  pound  of  coal  in  combustion  .  .148 

Air  the  only  gas  suitable  for  compression  as  a  motive  power     149 

XVI.  TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES. 

Importance  of  losses  in  transmission    .         .         .         .         .149 

No  loss  by  condensation  in  transmitting  air ;  Law  defining 
the  relations  between  water  and  any  elastic  fluid  .  .150 

Discharge  of  fluids  through  orifices  ;  Limitation  of  the  appli- 
cation of  the  formula  for  gravity  .  .  .  .  .151 

Mr.  R.  D.  Napier's  experiments  on  steam ;  Velocity  of 
steam  escaping  from  an  orifice  .  .  .  .  .152 

Constancy  of  the  velocity  and  of  the  weight  of  steam  ;  Re- 
sistance of  long  pipes  to  the  flow  of  elastic  fluids  ;  Experi- 
ments on  the  friction  of  air  .  .  .  .  .  .153 

Experiments  at  the  Mt.  Cenis  tunnel  .         .          .          .          .154 

Peculiarity  observable  in  using  tables  for  the  friction  of 
elastic  fluids  through  pipes,  and  its  explanation  .  .155 


XIV  CONTENTS. 

PAGE 

Demonstration  of  the  law  of  the  discharge  of  elastic  fluids 
through  long  pipes  ;  Fundamental  law  on  which  the  solu- 
tion of  all  problems  relating  to  steam  transmission  must 
depend  .  .  .  .  .  .  .  .  .  .157 

Experiments  of  Mr.  Holly  and  Mr.  Gaskill          .         .         .163 

Friction  of  air  in  pipes,  as  determined  from  the  experiments 
at  the  Mt.  Cenis  tunnel ;  Loss  of  tension  per  1000  metres 
of  pipe 165 

Table  giving  the  discharge  of  steam  at  the  volume  of  atmos- 
pheric tension,  the  corresponding  water  discharge  under 
same  head,  diameter  and  length  being  taken  as  unity,  and 
pressures  varying  by  half  atmospheres  from  one  to  ten  .  167 

Table  of  Thomas  Box  for  the  friction  of  air,  steam,  and  gas 
in  long  pipes  ;  Formula  of  Weisbach  for  the  friction  of  air 
through  long  pipes 168 

Fallacious  rule  of  the  engineer's  pocket-books  regarding  the 
discharge  of  air ;  Pipes  of  equivalent  resistances  .  .169 

Formula  for  calculating  tables  of  loss  of  head  by  friction     .     1 70 

Table  of  loss  by  friction  for  steam  in  pounds  per  square  inch 
for  one  mile  of  pipe  .  .  .  .  .  .  .172 

Capacity  of  mains  and  velocity  of  steam ;  The  limit  of 
velocity  .  . 173 

Table  of  discharges  of  steam  in  cubic  feet  per  second  for  a 
length  of  one  hundred  feet  .  .  .  .  .  .175 

Evaporation  of  water  under  pressure  ;  Difference  of  evapora- 
tion under  pressure  .  .  .  .  .  .  .176 

Table  of  evaporation  .         .         .         .         .         .          .177 

Steam  required  per  horsepower;  Usual  charge  per  horse- 
power in  Philadelphia  .  .  .  .  .  .  .178 

XVII.     GENERAL  SUMMARY. 

Reasons  for  the  small  amount  of  information  given  by  the 

published  reports  of  street  railway  companies  .  .  .179 
Horse-cars;  Cost  of  feed  per  horse  per  day  .  '".  .  181 
Steam  motors ;  Ammonia  motor  .  .  .  .  .  182 


CONTENTS.  XV 

PAGE 

Reasons    for   the  abandonment  of  the  ammonia  motor,  as 
given    by  General   Beauregard ;    The   hot- water   motor ; 
The  prominent  feature  in  the  hot- water  system         .         .183 
Defect  of  the  hot-water  system;  Gas  motors        .         .          .184 
Advantages  and  disadvantages  of  gas  motors       .         .         .185 
President  Yerkes  on  the  result  of  experiments  with  motors ; 
Pneumatic  and  compressed  air  motors  ;  Advantages  of  the 
pneumatic  motor     .          .          .         .          .         .          .          .186 

A  peculiar  feature  of  the  Hardie  motor ;  Test  of  the  Hardie 
pneumatic  motors  on  the  Second  Avenue  street  railroad, 

New  York,  in  1879 .         .188 

Reasons  for  the  failure  of  the  adoption  of  the  Ilardie  system     189 
Expiration  of  the  old  patents      .         .          .          .         .         .190 

Amount  of  air  required  to  run  the  Hardie  motor  .         .191 

Improvements  in  compressors  ;   Facilities  of  making  addi- 
tions to  the  plant ;    Electric   motors ;    Objection  to  the 
trolley  system  in  cities     .         .         .         .         .         .         .192 

The  electric  system  of  the  city  of  Richmond       .         .         .193 
The  cable  system  ;   Advantages  of  independent  motors  over 

any  cable  system .194 

Description  of  a  motor  examined  in  1879,  which  was  evi- 
dently a  fraud 195 

The  Keely  motor 196 


APPENDIX. 

Judson  low-pressure  air  storage  system  ;  Difference  of  this 
from  other  systems  .  .  .  .  .  .  .199 

Claims  of  the  Judson  Company  identical  with  those  of  the 
Hardie  motor  of  1879  ;  Estimate  of  the  Judson  system  .  200 

Electric  steam  motor  .         .         .         .         .         .         .     202 

INDEX  205 


STREET  RAILWAY  MOTORS. 


i. 

HORSE  RAILWAYS. 

HORSE  RAILWAYS,  as  also  all  other  railways  operated 
by  independent  motors,  require  merely  a  surface  track, 
the  cost  of  which  may  vary  from  $5000  to  $40,000  per 
mile  of  single  track  ;  $5000  supposes  a  light  45-pound 
rail  laid  on  cross-ties,  very  light  grading,  and  no  paving. 
Such  a  track  might  suit  for  a  suburban  extension  of 
a  city  line  in  a  sparsely-settled  district.  A  more  safe 
general  average  of  cost  will  be  taken  at  $10,000  per 
mile  as  a  standard  for  comparison  of  cost  of  plant  and 
operation  for  the  various  systems  to  be  considered. 

It  will  be  understood,  as  a  matter  of  course,  that  before 
commencing  construction  a  competent  engineer  should  be 
employed  to  prepare  plans,  profiles,  and  estimates  upon 
which  the  financial  arrangements  must  be  based ;  but 
$10,000  may  be  taken  as  a  fair  average  for  surface  roads, 
and  will  answer  as  a  basis  for  comparison  of  cost  of  plant 
in  the  systems  under  consideration. 

COST  OF  PLANT. 

One  of  the  reports  of  the  Second  Avenue  Railroad, 
of  New  York,  gave  number  of  cars  167,  number  of 

1 


'2  STREET   RAILWAY   MOTORS. 

horses  1197,  cost  of  cars  $92,800,  average  cost  of  one  car 
$556.  The  interest  paid  on  car-shed  and  stable  prop- 
erty was  $24,150,  representing  a  capital  of  $402,500. 
The  length  of  road  operated  8  miles  of  double  track  ; 
number  of  horses  to  one  car  10. 

With  these  data  the  cost  of  plant  may  be  approxi- 
mately estimated  on  the  Second  Avenue  Railroad  : — 

16  miles  single  track,  $10,000    ....  $160,000 

167  cars 92,800 

1197  horses,  $150 179,550 

Real  estate,  car-sheds,  and  stables      .         .         .     402,500 
Harness,  furniture,  and  incidentals    .         .         .       50,000 

Cost  of  plant  for  8  miles,  based  on  cost  of 

Second  Avenue  Railroad,  of  New  York     .  $884,850 

It  was  stated  that  the  average  cost  per  car  was  only 
$556.  This  is  below  the  average.  A  new  16-foot  car 
costs  from  $750  to  $1500  for  the  body  alone,  and  trucks 
about  $600.  In  estimating  the  cost  of  new  plants,  there- 
fore, it  will  not  be  safe  to  allow  less  than  $1000  per  horse- 
car,  to  which  the  cost  of  horses  must  be  added. 

The  number  of  cars  was  given  in  the  report  as  167, 
but  it  was  stated  that  this  number  included  many  old 
and  comparatively  useless  cars,  and  that  the  average 
number  in  daily  use  was  about  105,  or  only  60  per 
cent,  of  the  whole  number. 

Expenses  of  Operation. 

Repairs  of  harness     ..*...  $1,200 

Horse-shoeing 16,593 

Horses .42,000 

Stable  expenses           .         .         .         .         .         .  46,542 

Feed 108,785 

Interest  and  depreciation  in  horses,  etc.     .         .  17,490 

Interest,  taxes,  and  insurance  on  stables   .         .  12,000 

Cost  of  horse-power  one  year       .         .         .$244,610 


HORSE   RAILWAYS.  3 

Allowing  72  miles  as  the  average  daily  run,  and  105 
cars  in  average  daily  use,  the  annual  car-miles  would 
be  2,759,400,  and  the  cost  of  horse-power  per  car-mile 
would  be  9  cents,  exclusive  of  conductors,  drivers,  car 
expenses,  or  track  repairs. 

The  other  expenses  of  operation  were — 

Repairs  of  cars $29,000 

Interest  and  depreciation  of  cars         .         .         .  9,200 

Conductors  and  drivers       .....  167,335 

Interest  and  repairs  of  car-sheds  (est.)       .         .  16,000 

Total  car  expenses       .         .         .         .         .  $221,535 

Track  expenses : — 
16  miles  single  track,  $2932  per  mile  .         .         .  $46,912 

The  most  satisfactory  unit  for  comparison  of  expenses 
of  different  systems  is  the  car-miles,  and  in  the  case  under 
consideration,  the  car-miles  being  taken  at  2,759,400, 
the  results  are  : — 

Cost  of  horse-power 9   cents. 

Car  expenses       .         .         .         .         ...         .     8        " 

Track  repairs 1.68" 

The  total  expenses,  including  a  dividend  of  $72,000,  were 
$730,409,  which  would  leave  for  general  and  incidental 
expenses  a  balance  of  $145,409,  and  the  total  expenses 
may  be  thus  stated  : — 

Power  alone    .         .         .  $244,610,  per  car-mile     9   cents. 

Cars  and  conductors        .     221,535,    "      "      "       8        " 

Track  repairs  .         .      46,912,    "      "      "        1.68  " 

General    and    incidental 

expenses      .         .         .    145,409,    "      "      "        5.30  " 

$658,466  23.98  " 

The  total  number  of  passengers  carried  on  the  Second 
Avenue  Railroad  for  the  year  under  consideration  was 


4  STREET   RAILWAY   MOTORS. 

16,062,560,  and  the  cost  per  passenger  carried  was  4.55 
cents,  which  included  the  dividend  of  $72,000.  Exclu- 
sive of  dividend,  the  cost  was  4.10  cents. 

From  the  reports  of  16  horse-car  companies  in  the 
city  of  New  York,  operating  102  miles  of  road,  with 
1297  cars  and  10,301  horses,  it  appears  that  the  expenses 
for  one  year  were  : — 

Repairs  of  harness       .         .        $41,861,  per  horse  $4.06 

Shoeing  horses     .         .         .        234,578,    "       "  22.77 

Feed 1,281,316,    "        "  124.39 

Stable  expenses            .         .        434,014,    "        "  42.13 

Replacing  horses           .         .        227,693,    "        "  22.10 

$2,219,462  $215.45 

Cost  of  one  horse  one  month  $18,  number  of  horses  to 
one  car  8. 

If  the  whole  equipment  were  in  daily  use,  running 
72  miles  per  day  for  365  days,  the  car  mileage  would 
amount  to  34,075,000  miles,  and  the  cost  of  horse-power 
per  car-mile  would  be  6  J  cents  ;  but  if  the  same  propor- 
tion of  cars  were  in  daily  use  as  on  the  Second  Avenue 
Railroad,  the  car  mileage  would  be  20,445,000,  and  the 
cost  per  car-mile  10.8  cents. 

Charles  H.  Davis,  C,  E.,  gives  some  useful  data  in 
reference  to  street  railways. 

For  45  horse  railroads  in  Massachusetts,  from  1885 
ito  1890,  the  total  average  investment,  real  estate,  road, 
and  equipment,  is  given  : — 


HORSE   RAILWAYS.  5 

Per  mile  of  street       .   ^'J'-    .  '  "  . "       .  $33,406.00 

"      "     of  track        .    ^.    .    *         .         .  $31,093.00 

Car-miles  per  annum  per  mile  of  street       .  43,345 
Passengers  carried  per  annum  per  mile  of 

street .  251,816 

Passengers  carried  per  car-mile           .         .  5.81 

Operating  expenses       "          "     .         .         .  24.32  cents. 
Interest  at  6  per  cent,  on  investments  per 

car-mile 4.62      " 

Total  interest  and  operating  expenses         .  28.94      " 

Cost  per  passenger  carried,  interest  excluded  4.18       " 

"       included  4.98      " 

Conditions  stated  by  C.  H.  Davis,  in  comparative 
estimates :  Horse-cars,  72  miles  per  day,  running  18 
hours,  4  miles  per  hour.  Depreciation  of  horses,  20 
per  cent. ;  of  cars,  5  per  cent.  Track  repairs  and  de- 
preciation, 10  per  cent.  3  men  per  car,  $1.60  each. 
Value  of  car  and  horses,  $1900.  6  horses  per  car. 
Keep,  35  cents  per  day. 

In  Rochester,  the  earnings  of  horse  railways  for  June, 
1891,  were  14.37  cents  per  car-mile,  and  expenses  11.06 
cents,  as  reported.  Those  of  the  West  End  Company 
of  Boston  for  same  time  were :  Earnings,  34.28  cents 
per  car-mile  ;  expenses,  24.03. 

The  number  of  rides  per  capita  in  cities  of  population 
from  20,000  to  30,000  is  given  as  an  average  of  30,  in- 
creasing regularly  to  190  with  increase  of  population  to 
800,000  or  over. 

A  census  bulletin  issued  by  Superintendent  Porter 
gives  statistics  of  30  roads  operated  by  animal  power 
with  552  miles  of  track.  Total  cost,  with  equipment, 
$22,788,277.  Operating  expenses,  $6,986,019.  Pas- 
sengers carried,  190,434,783.  Expenses  per  car-mile, 
18.16  cents.  Cost  per  passenger,  3.67  cents. 


6  STREET    RAILWAY    MOTORS. 

A  report  of  earnings  and  expenses  of  the  West  End 
Company  of  Boston  for  April,  May,  and  June,  1892, 
per  car-mile  for  horse-cars,  including  motive  power,  car 
repairs,  damages,  wages,  and  other  expenses,  gives : — 

Cents. 
Earnings  per  car-mile    .         .          .         .          .         .34.28 

Expenses       "          " 24.03 

Net  receipts 10.25 

Another  report  of  the  West  End  Company  for  April, 
May,  June,  July,  and  August,  1891,  gives  for  the  horse 
railroad  : — 

Cents. 
Motive  power  per  car-mile,  average  of  5  months     .     10.60 

Car  repairs  "          " 0.56 

Damages  "          " 0.30 

Conductors  and  drivers  .         .         .         .         .8.22 

Other  expenses       .......       4.77 

Total  expenses .24.50 

Earnings 35.20 

Net  earnings  per  mile 10.71 

Mr.  H.  H.  Windsor,  editor  of  Street  Railway  Re- 
view, of  Chicago,  in  reply  to  a  private  letter,  states 
that  there  is  a  difficulty  in  procuring  reliable  informa- 
tion in  regard  to  statistics  of  horse  railway  companies, 
arising  from  the  fact  that  there  is  no  general,  uniform 
system  of  accounts  such  as  prevails  amongst  railroads ; 
but  that  for  the  year  1890  he  has  his  own  figures,  com- 
piled while  secretary  of  the  Chicago  City  Eailway,  and 
which  show  all  the  expenses  except  interest  and  divi- 
dend, being  21.98  cents  per  car-mile  for  horse  roads. 

Since  that  time  the  cost  of  horse-power  has  increased, 
owing  to  increased  cost  of  feed,  and  for  the  last  year  the 
total  expenses  have  been  24  cents. 


HORSE   RAILWAYS.  7 

The  most  important  datum,  in  comparison  of  cost  of 
operation  of  the  different  systems,  is  the  power  required 
for  propulsion  ;  and  its  cost  per  car-mile,  from  the  data 
furnished,  would  appear  to  be,  with  horses  for  the  power 
alone,  exclusive  of  conductors,  drivers,  or  other  expenses 
outside  the  stables,  from  9  to  10  cents  per  car-mile. 

The  total  expenses  for  horse  service  appear  to  be 
nearly  uniform  at  about  24  cents  per  car-mile. 

In  a  comparison  of  expenses  of  operation  between 
horse-power  and  other  motors,  it  will  be  convenient  to 
ascertain  the  percentages  which  the  several  items  bear 
to  the  whole  motive-power  expense. 

Per  cent. 

Repairs  of  harness  .         .         .         .         .         .  .  0.5 

Horse-shoeing  .         .         .         ......  .  7.0 

New  horses      .         •         .         .....  .  17.0 

Stable  expenses        .         .         .   •     .         .         .  .  18.0 

Feed ;  .  50.0 

Interest,  taxes,  insurance,  miscellaneous         .  .  7.5 

100.0 

If  the  cost  of  horse-power  per  car-mile  be  taken  at  an 
average  of  10  cents,  then  the  cost  of  each  of  the  above 
items  will  be  : — 

Repairs  of  harness  ......  ^  mill. 

Horse-shoeing          ......  7  mills. 

New  horses      .......  1.7  cents. 

Stable  expenses 1.8      " 

Feed 5.0      " 

Other  expenses        .         .         .                  .         .  7£  mills. 

10  cents. 


STREET   RAILWAY   MOTORS. 


II. 

STEAM  MOTORS. 

STEAM  MOTORS  for  street  railways  are  now  but  little 
used.  Wherever  tried  they  have  in  general  been  aban- 
doned and  some  other  mode  of  propulsion  adopted.  A 
brief  consideration  of  steam  motors,  however,  seems  to 
be  necessary  as  one  of  the  steps  in  the  transition  to  the 
present  more  popular  systems,  and  as  illustrating  prin- 
ciples applicable  to  the  use  of  other  elastic  fluids  in  other 
forms  of  motors. 

Water  is  composed  of  2  volumes  of  hydrogen  united 
to  1  volume  of  oxygen,  the  union  forming  2  volumes  of 
steam  ;  and  the  weight  of  1  volume  of  steam,  hydrogen 
being  unity,  is  8.98,  so  if  air  is  taken  as  unity  the  den- 
sity of  steam  at  atmospheric  pressure  will  be  0.561. 

The  maximum  density  of  water  is  at  4°  Centigrade,  or 
39.2°  Fahrenheit.  Below  this  point  water  expands 
until  frozen  at  0°  C.  or  32°  F.,  forming  ice,  and  in  freez- 
ing water  expands  from  1  to  1.09  of  its  volume. 

Ice  melts  at  32°  F.,  and  there  can  be  no  rise  of  tem- 
perature until  all  the  ice  is  melted. 

In  passing  from  the  solid  to  the  liquid  state  a  given 
weight  of  water  takes  up,  or  renders  latent,  just  so  much 
heat  as  would  suffice  to  raise  the  same  weight  of  water 
through  79°  C.  or  142°  F.  The  latent  heat  of  water  is, 
therefore,  said  to  be  79  thermal  units  C.  or  142  thermal 
units  F. 

When  heated  to  100°  C.  or  212°  F.,  in  the  open  air 


STEAM   MOTORS.  9 

at  ordinary  pressure  of  the  atmosphere  at  sea-level,  water 
boils  and  steam  is  formed.  In  this  second  change  of 
form  from  fluid  to  vapor -another  large  portion  of  heat 
becomes  latent.  The  thermometer  would  indicate  no 
change  of  temperature,  but  in  the  transformation  536 
thermal  Centigrade  units,  or  967  thermal  Fahrenheit 
units,  disappear  or  become  latent. 

In  scientific  books  and  in  foreign  countries  the  Cen- 
tigrade thermometer  and  the  French  decimal  system  of 
weights  and  measures  are  generally  used.  The  Centi- 
grade graduation  makes  the  freezing-point  0,  and  the 
boiling-point  100.  The  kilogramme  is  used  for  weight, 
which  is  equivalent  to  2.2047  Ibs.  avoirdupois.  In  the 
Fahrenheit  scale,  which  will  hereafter  be  used  to  avoid 
confusion,  the  freezing-point  is  32°  and  the  boiling-point 
212°.  1°  Centigrade  is  therefore  equivalent  to  1.8° 
Fahrenheit. 

The  temperature  at  which  water  boils  is  dependent 
upon  the  pressure.  Under  the  exhausted  receiver  of  an 
air-pump,  and  on  the  tops  of  mountains,  the  boiling- 
point  is  lower,  and  in  steam  boilers,  under  pressure,  it 
may  be  almost  indefinitely  increased. 

Other  fluids  boil  at  very  different  temperatures ;  some 
of  them,  such  as  liquid  ammonia,  boiling  at  a  tempera- 
ture much  below  the  freezing-point  of  water. 

Specific  heat  is  the  thermal  capacity  of  a  given  quan- 
tity of  any  substance,  and  the  thermal  capacity  is  the 
quantity  of  heat  necessary  to  raise  the  temperature  1°  in 
the  absolute  thermodynamic  scale  which  commences  at 
the  theoretical  zero  of  — 460°  Fahrenheit,  water  being 
taken  as  the  unit.  The  specific  heat  of  ice  is  0.513,  of 
cast-iron  0.140,  of  air  and  approximately  of  other  gases 


10  STREET   RAILWAY    MOTORS. 

under  constant  volume  and  atmospheric  pressure  0.250, 
and  of  steam  0.475. 

The  fuel  required  for  the  conversion  of  water  into 
steam  constitutes  the  principal  item  of  expense  in  the 
conversion  of  heat  into  work,  and  is  the  most  important 
datum  in  the  comparison  of  the  economical  efficiency  of 
different,  systems. 

The  fuel  usually  employed  is  coal,  but  in  many  cases 
petroleum  has  been  used  to  great  advantage. 

One  pound  of  pure  carbon  requires  2f  pounds  of 
oxygen  for  perfect  combustion  with  conversion  into  car- 
bonic acid,  and  this  quantity  of  oxygen  would  be  fur- 
nished by  12.2  pounds  of  air,  the  result  being  13.2 
pounds  of  gases  heated  by  14,544  units  of  heat,  and 
giving  a  theoretical  absolute  temperature  of  5150 
degrees. 

Air  at  32°  F.  volume  1  cubic  foot,  weighs  0.0807  Ib. 
or  12.39  cubic  feet  to  one  pound,  and  12.2  Ibs.  would 
require  151.16  cubic  feet. 

The  greatest  possible  evaporation  of  water  from  one 
pound  of  carbon,  if  all  the  heat-units  could  be  utilized, 
would  be  14.87  pounds. 

In  practice  it  is  not  possible  to  introduce  and  distrib- 
ute air  in  the  exact  proportion  required  for  perfect  com- 
bustion, and  a  portion  of  fuel  must  remain  unconsumed, 
or  a  portion  of  the  heat-units  expended  without  useful 
effect  in  heating  a  surplus  of  air. 

The  best  quality  of  coal  should  yield  in  combustion 
about  14,000  units  of  heat;  but  13,000  would  probably 
be  nearer  the  ordinary  average. 

To  raise  one  pound  of  water  from  the  ordinary  tem- 
perature of  60°  to  212°  would  require  152  thermal 


STEAM   MOTORS.  11 

units.  To  convert  1  pound  of  water  into  steam  at  212° 
requires  967  units  in  addition,  and  to  raise  this  steam  to 
a  pressure  of  150  pounds,  temperature  360°,  the  specific 
heat  of  steam  being  0.475,  will  require  148  x  0.475  =  70 
units  more,  making  a  total  of  1189  units. 

If  13,000  units  could  be  utilized  in  1  pound  of  coal, 
the  evaporation  would  be  1 1  pounds  of  water  from  60° 
F.  ;  but  in  ordinary  practice  in  locomotive  engines  the 
evaporation  is  about  6  pounds,  and  in  small  motors  even 
less. 

Steam  at  150  Ibs.  pressure  has  3  cubic  feet  of  volume 
per  pound,  and  6  pounds  would  occupy  18  cubic  feet  of 
space  in  the  boiler. 

The  full  value  of  the  thermal  units  contained  in  the 
boiler  steam  cannot  be  utilized.  The  exhaust  in  a  loco- 
motive is  always  under  considerable  pressure,  which  re- 
duces the  mechanical  effect.  The  exhaust  steam  condens- 
ing into  water  loses  the  967  thermal  units  required  for 
its  change  from  fluid  to  vapor  with  its  1700-fold  increase 
of  volume.  There  are  also  other  losses  between  the 
boiler  and  the  cylinders  by  radiation  and  friction,  so 
that  to  calculate  the  useful  mechanical  effect  in  a  small 
street  motor  from  the  number  of  thermal  units  in  the 
boiler  presents  too  many  elements  of  uncertainty  for  the 
results  to  be  relied  upon. 

Ordinary  locomotives  on  railroads  evaporate  from  20 
to  150  gallons  of  water  per  mile  run,  the  average  being 
40  for  passenger  engines  and  80  for  freight.  The  Read- 
ing Railroad  used  per  ton-mile  0.31  pound  for  passen- 
ger engines  and  0.11  for  freight. 

The  consumption  of  coal  averages  80  pounds  per 
square  foot  of  grate  surface  per  hour ;  the  evaporation 


12  STREET   RAILWAY   MOTORS. 

not  more  than  6  pounds  of  water  per  pound  of  coal,  or 
about  one-half  the  theoretical  possibility. 

The  consumption  of  steam  per  horse-power  per  hour 
is  25  pounds,  the  maximum  possible  evaporation  600 
pounds  per  square  foot  of  grate  surface.  The  evapo- 
ration at  6  pounds  of  water  to  1  pound  of  coal  and  80 
pounds  of  coal  per  hour  per  square  foot  of  grate  would 
be  480  pounds,  yielding  19.2  horse-power  per  square 
foot  of  grate  surface. 

The  horse-power  required  to  propel  an  ordinary  street 
motor  operated  by  steam  can  be  determined  with  a  con- 
siderable degree  of  accuracy  from  observations  made  by 
the  writer  in  1879  on  the  power  required  to  propel  street 
motors  by  compressed  air. 

In  these  tests  the  motor  cylinders  were  6Jx  13  inches, 
the  number  of  revolutions  of  wheels  per  mile  720,  the 
piston  travel  per  mile  in  the  two  motor  cylinders  3120 
feet,  the  speed  6  miles  per  hour,  the  piston  travel  18,120 
feet  per  hour,  the  mean  piston  pressure  56.64  pounds  per 
square  inch  on  an  area  of  33.18  square  inches,  making 
total  piston  pressure  1879  pounds. 

„,,        18120  x  1879       170  ,  ..   ,   . 

I  hen, =  17.2,  horse-power  applied  to 

33000  x  60 
piston. 

Wellington,  in  his  Economic  Theory  of  Railways,  page 
451,  states  that  the  consumption  of  steam  per  horse-power 
per  hour  is  rarely  better  than  25  pounds,  and  often  much 
worse. 

If,  then,  the  evaporation  under  the  pressure  assumed 
of  150  pounds  per  square  inch  be  taken  at  6  pounds  of 
water  to  1  pound  of  coal,  and  if  it  be  assumed  that  17.2 
horse-power  in  cylinders  will  require  at  least  20  horse- 


STEAM   MOTORS.  13 

power  in  boilers,  the  consumption  of  coal  per  hour  would 

20  x  25 
be  —          —  =  83  pounds,  and  per  mile  14  pounds,  which, 

6 

at  3  mills  per  pound,  or  $6  per  ton,  would  be  4.2  cents 
per  mile.  For  small  street  motors  this  result  seems  to 
be  in  excess  of  the  true  average. 

Steam  motors  should  run  100  miles  per  day,  and, 
allowing  for  repairs,  300  days  in  the  year,  or  30,000 
miles.  They  would  cost  about  $3000;  while  10  horses 
to  one  car,  running  the  same  distance,  would  cost  $1500  ; 
but  as  a  motor  with  50  per  cent,  increase  of  capacity 
could  haul  two  cars  and  at  greater  speed,  the  number  of 
motors  required  would  be  less  than  the  number  of  cars, 
and  the  excess  in  the  cost  of  motors  over  horses  would 
not  be  very  great. 

If  a  road  be  supposed  6  miles  long,  requiring  a  round 
trip  of  12  miles,  and  a  steam  motor  to  run  at  8  miles 
per  hour,  and  2-minute  intervals^  the  round  trip  would 
require  90  minutes,  and  the  number  of  motors,  without 
allowance  for  reserve,  would  be  45. 

If  operated  by  horse-power  at  a  speed  of  4  miles  per 
hour,  and  10  horses  to  a  car,  the  round  trip  would  re- 
quire 3  hours ;  the  cost  of  horses  would  be  about  the 
same  as  the  cost  of  motors,  but  the  number  of  cars 
would  be  doubled. 

If,  in  consequence  of  municipal  restrictions  or  other 
causes,  the  speed  should  be  limited  to  6  miles  per  hour, 
the  number  of  motors  and  cars  would  be  increased  33 
per  cent. 

Taking,  as  a  basis  of  comparison,  2-minute  intervals 
between  cars,  speed  of  horses  4  miles  per  hour  and  of 
motors  6  miles,  and  a  reserve  of  25  per  cent.,  length  of 


14  STREET   RAILWAY   MOTORS. 

road  6  miles  and  round  trip  12  miles,  the  number  of 
cars  required  for  horses  would  be  112  and  for  motors 
75,  making  a  saving  of  $37,000  in  car  equipment  with 
steam  motors. 

The  reduced  number  of  cars  would  reduce  car  repairs 
about  J  of  a  cent  per  car-mile,  and  conductors  1 J  cents. 

The  cost  of  horses  would  nearly  balance  the  cost  of 
motors,  taking  into  consideration  reduced  time  of  round 
trip. 

Engineers  would  be  more  expensive  than  drivers,  but 
the  number  would  be  less. 

Fuel  would  cost  less  than  horse-feed.  Shoeing  would 
balance  repairs. 

Trautwein  gives  the  amount  of  coal  consumed  per  ton- 
mile  in  ordinary  passenger  trains  as  0.31  Ib. ;  but  as  trac- 
tion on  roads  in  good  order  is  at  least  one-half  as  much  as 
on  street  railroads  per  ton,  the  proportionate  consump- 
tion of  coal  may  be  taken  at  0.65  Ib.  for  steam  motors. 

Assuming  the  weight  of  the  motor  at  8  tons  and  of 
the  car  at  5  tons,  the  total  will  be  13  tons,  and  the  con- 
sumption of  coal  with  these  data  about  9  pounds  per 
mile. 

No  data  are  accessible  for  an  accurate  determination 
of  the  coal  consumed  in  a  small  steam  motor  for  street 
service,  and  the  foregoing  estimates  include  many  ele- 
ments of  uncertainty.  Another  estimate  will  be  at- 
tempted on  a  basis  that  would  seem  to  be  more  reliable. 

The  consumption  of  free  dry  air  in  the  Hardie  motor 
of  8  tons  was  found  to  be  720  cubic  feet  per  mile  run. 
One  pound  of  steam  at  212°  =  27  cubic  feet;  720  cubic 
feet  =  27  pounds  of  steam,  requiring  5  pounds  of  coal 
for  8  tons ;  13  tons  would  therefore  require  10.6  pounds 


STEAM    MOTOES.  15 

for  a  train  of  motor  and  car.  It  will  probably  be  safe 
therefore  to  estimate  the  consumption  at  10.6  pounds  per 
mile  run.  The  motor  not  being  suitable  for  carrying 
passengers,  a  weight  of  13  tons  is  required  as  against 
8  tons  with  equal  carrying  capacity  in  systems  in  which 
car  and  motor  can  be  combined.  The  cost  for  coal  in 
this  system  will  be  2.65  cents  per  train-mile. 

The  repairs  of  cars  drawn  by  motors  can  be  taken  as 
the  same  cost  per  car-mile  as  by  horses,  which  is  1J 
cents,  and  the  cost  per  day  $76.80. 

COST  OF  ENGINES. 

The  cost  of  small  engines  is  much  larger  in  proportion 
to  weight  than  the  cost  of  large  ones.  Large  engines 
cost  $286  per  ton  of  weight ;  small  engines  from  $383 
to  $400  per  ton.  An  engine  weighing  8  tons  should 
cost,  at  this  rate,  $3200.  The  smallest  mine  engines 
manufactured  at  the  Baldwin  Locomotive  Works  cost 
$2500. 

REPAIR  OF  MOTORS. 

The  cost  of  repairs  on  ordinary  passenger  engines  is 
about  7  cents  per  mile  run.  Small  engines  will  cost 
much  more  in  proportion  to  weight.  It  is  possible  that 
the  cost  of  repair  of  street  motors  may  be  covered  by 
4  cents  per  mile  run. 

DEPRECIATION. 

The  depreciation  of  motors  will  be  taken  at  15  per 
cent.,  of  cars  5  per  cent.,  of  buildings  3  per  cent. 


16  STREET   RAILWAY   MOTORS. 


PLANT  REQUIRED. 

Double  the  track-room  will  be  required  for  cars  and 
motors  that  would  be  needed  for  the  cars  alone;  and 
repair  shops  will  also  be  necessary  for  repairs  of  engines. 

Plant  Required  for  6  Miles  of  Double  Track  to  be 
Operated  by  Steam  Motors. 

Real   estate,    motor  and  car-sheds,   shops   and 

offices,  40,000  square  feet  land,  $1.50      .         .     $60,000 
Buildings  and  machinery  for  repairs  .         .     100,000 

$160,000 

Street  Construction. 

1  mile  double  track $20,000 

9282  sq.  yds.  paving,  $3 27,846 

Cost  of  one  mile $47,846 

Cost  of  six  miles  .         .         .         .  287,076 

Rolling  Stock. 

75  steam  motors,  $3000 $225,000 

75  trail  cars,  $1000 75,000 


$300,000 


Summary  Cost  of  6  Miles. 


Real  estate          .         .         .         ..        .  .  .  $160,000 

Track  and  paving       .         .         .         .  '  -.  .     287,076 

Rolling  stock      .         ...         .  .     300,000 

Miscellaneous  expenses       .         .         .  .  .       20,000 

Cost  of  6  miles    .        . "       .  •    •.  .  .  $767,076 

Cost  of  1  mile      .         .         .         .  .  .$127,846 


AMMONIA   MOTOR.  17 

Cost  of  Operation  of  6  Miles  Double  Track  For  One 
Day  With  Steam  Motors. 

30  tons  coal  at  $5  per  ton  .         .    *    .         .         .  $150.00 

Waste,  oil,  and  grease        .  -       .         .         .         .  25.00 

Depreciation  of  plant  and  rolling  stock      .         .  127.00 

60  conductors,  $2 120.00 

60  engineers,  $3          ......  180.00 

60  firemen,  $1.50 90.00 

Car  and  engine  house  expenses           .         .         •  42.00 

Motor  repairs,  5760  miles,  4  cts.          .         . '    .    <•  230.40 

Car  repairs          .......  76.80 

Track  service 16.00 

Repair  of  track  and  buildings    ....  60.00 

Clearing  track,  train  and  shop  expenses     .         .  25.00 

Accidents 20.00 

Legal  and  other  expenses  .         ,.        .         .         ,  10.00 

General  and  miscellaneous  expenses           .    .     .  50.00 

5760  train-miles  cost   .         „:       .         .        .$1222.20 
Cost  per  car-mile          ...         •         .      21.22  cents. 


III. 

AMMONIA  MOT 

AMMONIA,  at  ordinary  temperaturesl^^j^ffiajient 
gas  formed  by  the  union  of  three  volumes  of  hydrogen 
with  one  of  nitrogen,  condensed  into  two  volumes.  Its 
density  is  0.596,  air  being  1.000. 

When  condensed  into  a  liquid  the  density  is  76,  water 
being  100. 

Ammonia  vapor  at  60°  Fahrenheit  gives  a  pressure  of 
100  pounds  to  the  square  inch,  while  water,  to  give  an 
equivalent  pressure,  must  be  heated  to  325°  F. 
2 


18  STEEET    RAILWAY   MOTORS. 

The  volume  of  ammoniacal  gas  under  100  Ibs.  pres- 
sure is  980  times  greater  than  the  space  occupied  by  its 
liquid,  while  steam  under  the  same  pressure  occupies  a 
space  only  303  times  greater  than  water. 

Ammonia  liquefies  under  a  pressure  of  1 7  atmospheres, 
250  Ibs.  per  square  inch,  at  ordinary  temperatures,  and 
by  cold  alone  at  40°  below  zero. 

At  103°  F.  below  zero,  and  a  pressure  of  20  atmos- 
pheres, ammonia  is  condensed  into  a  white,  transparent 
crystalline  solid,  which  melts  at  103°  F.  below  zero. 

The  latent  heat  of  ammoniacal  gas  is  860,  that  of 
steam  being  967. 

The  solubility  of  ammoniacal  gas  in  water  is  remark- 
able. At  a  temperature  of  freezing,  water  will  absorb 
more  than  a  thousand  times  its  volume ;  at  50°  F.  more 
than  800  times,  and  at  70°  500  times. 

Knight's  American  Mechanical  Dictionary  states  that 
ammoniacal  gas  is  condensed  into  a  liquid  at  the  pressure 
of  the  atmosphere  at  a  temperature  of  — 37.3°  F.,  or 
— 38.5°  C.  At  the  boiling- point  of  water  it  requires  61 
atmospheres.  At  the  freezing-point  of  water  it  requires 
5  atmospheres  at  70°  F.,  a  pressure  of  9,  and  at  100° 
F.,  a  pressure  of  14. 

The  same  authority  states  that  the  economy  of  fuel  to 
obtain  a  given  pressure  is  very  great,  being  only  about 
one-fourth  the  amount  required  to  obtain  an  equal  pres- 
sure by  the  use  of  steam. 

As  ammonia  is  absorbed  the  water  becomes  specifically 
lighter,  while  its  volume  is  being  augmented  about  one- 
third.  As  the  absorption  of  the  gas  goes  on,  the  water 
becomes  heated  and  the  latent  heat  of  the  gas  reappears 
as  sensible  heat.  It  is  in  this  property  that  water  pos- 


AMMONIA   MOTOR.  19 

sesses,  of  absorbiDg  so  large  an  amount  of  the  gas  and  of 
becoming  heated  while  absorbing  it,  that  the  practica- 
bility of  using  ammoniacal  gas  as  a  motive  power  con- 
sists, the  only  agency  for  producing  motive  power 
being  heat. 

In  1871  an  ammoniacal  motor  was  constructed  at 
New  Orleans  by  Dr.  Emile  Lamm.  It  was  tested  and 
reported  upon  by  a  committee  of  which  General  G.  T. 
Beauregard  was  chairman,  and  the  report  of  this  com- 
mittee, with  the  accompanying  statement  of  the  inventor, 
Dr.  Lamm,  is  an  extremely  interesting  document  from 
which  much  of  the  information  here  given  has  been 
derived. 

Dr.  Lamm  does  not  claim  for  ammonia  the  ability, 
with  a  given  expenditure  of  heat,  to  produce  a  larger 
initial  force  than  with  water,  but  the  chief  advantage 
claimed  by  him  appears  to  consist  in  the  fact  that  the 
production  of  the  force  at  a  low  temperature  apparently 
allows  a  greater  portion  to  be  utilized.  He  remarks  : 
"  The  experience  of  nearly  a  century  since  the  perfection 
of  the  steam-engine  has  left  the  world  in  possession  of 
one  invaluable  fact,  that  any  system  of  mechanics,  how- 
ever ingenious,  not  based  on  a  like  expenditure  of  fuel 
in  the  heating  of  liquids,  while  all  obey  the  same  laws 
of  expansion,  has  invariably  proved  a  failure.  It  can 
now  be  positively  asserted  that  we  cannot,  with  a  given 
quantity  of  heat,  obtain  more  force  with  one  element 
than  with  another.  We  must  look  for  improvement  in 
the  machine  and  not  in  the  law. 

"In  the  various  forms  that  matter  assumes  the  physi- 
cist sees  only  one  primary  cause — heat.  A  unit  of  heat 
added  to  a  given  weight  of  any  substance  will  produce 


20  STREET   RAILWAY    MOTORS. 

a  like  development  of  force  in  all  equal  weights  of 
matter,  however  dissimilar  in  physical  appearance  or 
properties. 

"  One  holding  such  views  could  not  be  expected  to 
claim  for  himself  a  discovery  to  supersede  steam  as  a 
general  agent  of  mechanical  force. 

"In  that  most  remarkable  quality  which  water  pos- 
sesses of  being  converted  by  heat  into  a  medium  which 
is  as  yet  the  cheapest  of  all  mechanical  agents,  ammonia 
stands  fully  the  equal  of  water  in  economy,  with  this 
difference  only,  that  the  cost  of  the  necessary  quantity  of 
ammonia  to  run  an  engine  enters  as  first  cost,  with  a 
yearly  loss  of  25  per  cent,  to  be  added  thereon — the  price 
of  water  being  nominal.  While  ainmoniacal  gas  is  equal 
in  every  other  respect  to  steam,  except  in  the  first  cost  of 
the  material  generating  it,  it  possesses  qualities  that  will 
always  insure  its  use  as  an  economical  power  in  all  cases 
where  steam,  from  the  very  nature  of  its  production, 
could  not  be  used  to  the  same  advantage.  For  example, 
the  smallest  steam  engine  necessitates  a  personal  attend- 
ance but  little  less  costly  for  one-horse  power  than  for 
one  hundred.  So  it  is  with  the  manufacture  of  ammonia 
for  horse-cars.  A  still  of  100  horse-power  to  supply  100 
cars  will  cost  but  little  more  for  attendance  than  a  1 
horse  still.  But  here  the  resemblance  ceases.  The  large 
steam-engine  does  not  allow  of  any  division,  while  an 
-ammoniacal  still  of  100  horse-power  can  be  divided  into 
100  ammoniacal  engines  without  any  additional  expense. 
This  is  owing  to  the  fact  that  ammoniacal  gas  can  be 
liquefied  in  one  single  large  establishment,  from  which 
the  liquid  can  be  transported  at  any  time  thereafter  to 
any  distance  from  the  furnace  which  generated  it,  and 


AMMONIA    MOTOR.  21 

then  and  there  be  made  to  act  upon  an  engine  with  all 
the  pristine  force  of  tension  which  was  imparted  to  it  by 
a  fire  whose  ashes  have  been  cold  for  months  or  years 
past.7' 

Dr.  Lamm  concedes  that  the  point  at  which  a  liquid 
may  boil  below  the  common  temperature  makes  but  little 
difference  practically  between  the  heat  necessary  to  evapo- 
rate into  steam  a  given  amount  of  water  which  boils  at 
212°  F.,  and  one  that  boils  at  40°  minus,  such  as  ammo- 
nia :  the  real  and  only  difference  being,  comparatively, 
that  of  radiation  in  favor  of  the  liquid  that  boils  at  40° 
minus,  and  even  the  above  difference  would  seem  to  be 
more  apparent  than  real. 

"  If  it  was  necessary  to  heat  ammonia  or  a  street-car 
by  means  of  a  furnace,  ammonia,  then,  would  offer  but 
little  advantage  over  steam.'7 

It  appears,  therefore,  that  the  principal  advantage 
claimed  by  the  inventor,  Dr.  Lamm,  in  the  use  of  am- 
monia as  a  substitute  for  steam,  is  that  only  one  fire  at 
a  central  point  will  be  required  for  all  the  engines  on 
the  road,  the  power  in  the  shape  of  liquid  anhydrous 
ammonia  being  bottled  up  for  use  when  and  as  required  ; 
also,  some  advantage  by  diminished  loss  of  heat  by  radi- 
ation in  consequence  of  the  low  temperature  at  which  the 
gas  is  used.  It  is  not  claimed  that  the  natural  law  by 
which  a  unit  of  heat  is  the  equivalent  of  772  foot-pounds 
of  work  can  be  evaded.  Work  done  is  always  heat  lost. 
The  latent  heat  of  the  ammonia  gas  reappears  in  the 
water  of  condensation,  less  the  amount  expended  in 
work,  and  when  the  aqueous  solution  is  pumped  back 
into  the  still  all  the  lost  heat  must  be  restored  by  the 
combustion  of  coal.  In  consequence  of  the  superior 


22  STREET    RAILWAY   MOTORS. 

evaporative  power  of  stationary  as  compared  with  small 
locomotive  boilers,  the  ammonia  engine  should  effect  a 
large  saving  of  fuel,  if  not  counterbalanced  by  attendant 
disadvantages,  as  compared  with  small  steam  motors, 
but  as  compared  with  the  pneumatic  or  other  systems 
where  the  power  is  also  generated  by  a  large  central 
plant,  and  where  there  is  no  loss  by  radiation  or  conden- 
sation, the  advantages  are  not  apparent.  In  fact,  Dr. 
Lamm  himself  abandoned  the  ammonia  engine  after  a 
short  trial  in  favor  of  hot  water,  which  was  used  for 
some  years  on  the  street  roads  at  New  Orleans,  and  then 
the  company  returned  to  mule-power. 

Having  written  to  General  Beauregard  to  ascertain 
the  reasons  for  the  abandonment  of  ammonia  when  the 
report  of  the  committee  appointed  to  test  the  invention 
had  been  so  satisfactory,  the  General  replied,  under  date 
of  December  23, 1892,  that  no  difficulty  was  encountered 
in  the  use  of  Lamm's  Ammoniacal  Motor ;  but,  while 
experimenting  with  it,  Dr.  Lamm  discovered  the 
"  Heated  Steam  Motor,"  which  he  preferred  as  being 
cheaper  and  less  troublesome,  and  the  board  of  directors, 
of  which  General  Beauregard  was  president,  agreed  with 
him.  After  some  years  a  new  board  of  directors  came 
into  control,  who  abandoned  the  hot-water  motor  and 
returned  to  mule-power. 

After  twenty-one  years  the  subject  of  ammonia  motors 
appears  to  be  again  occupying  public  attention,  and  it  is 
therefore  proper  that  a  brief  description  of  Lamm's  Am- 
monia Engine,  as  used  in  1871,  should  be  given. 


AMMONIA  MOTOR.  23 

LAMM'S  AMMONIA  ENGINE. 

The  patent  bears  date  July  19,  1870,  and  describes 
an  addition  to  a  steam-engine  of  water-chambers  in- 
closing the  piston-rods  and  valve-stem,  so  as  to  render 
it  capable  of  being  worked  by  ammoniacal  gas  instead 
of  steam,  without  any  loss  of  the  gas,  which  is  returned 
to  the  common  tank,  while  the  exhaust  is  re-absorbed 
by  a  weak  solution  of  aqua  ammonia. 

The  second  part  of  the  invention  relates  to  the  appli- 
cation of  liquefied  ammoniacal  gas,  contained  in  a  con- 
siderable number  of  iron  tubes,  as  the  liquid  from  which, 
instead  of  water,  the  motive  power  of  the  engine  is  de- 
rived. 

The  third  part  relates  to  a  weak  solution  of  aqua  am- 
monia, contained  in  a  tank,  in  which  the  iron  tubes  are 
immersed,  and  in  which,  also,  the  exhaust  pipe  of  the 
engine  is  made  to  dip  near  the  bottom.  The  gas  ex- 
hausted while  the  engine  is  working  is  re-absorbed  by 
this  weak  solution  of  aqua  ammonia  until  the  solution 
becomes  saturated.  The  gradual  re-absorption  of  the 
gas  by  the  weak  solution  causes  the  latent  heat  of  the 
gas  to  re-appear.  This  re-transfer  maintains  a  constant 
temperature  within  the  tubes,  resulting  in  an  undimin- 
ished  pressure  from  expansion  of  the  liquefied  gas,  which 
maintains  the  motive  power  at  its  maximum  tension. 

The  process  of  liquefying  the  ammoniacal  gas  is  ren- 
dered continuous  by  a  fresh,  concentrated  solution 
pumped  back  into  the  boiler  to  replace  the  weak  solu- 
tion, which  is  drawn  off  from  its  bottom. 

It  is  claimed  that  3  pounds  of  coal  will  evaporate  3 
gallons  of  water,  while  3  pounds  of  coal  will  produce  4 


24  STREET    RAILWAY    MOTORS. 

gallons  of  liquid  gas.  One  gallon  of  water  under  6J 
atmospheres  at  320°  F.  =  295  volumes  of  steam  ;  one 
gallon  of  liquid  gas  under  6J  atmospheres  at  50°  F.  = 
983  volumes  of  gas. 

In  the  tests  made  by  General  Beauregard  1.44  gallons 
of  liquefied  gas  were  consumed  per  mile. 

The  weak  solution  put  in  at  15°  Baume  was  found  to 
weigh  23°  Baume'  at  end  of  trip,  having  been  increased 
by  absorption  of  gas  8°. 

5  gallons  of  commercial  aqua  ammonia  of  solution 
25°  Baume  can  be  delivered  at  New  Orleans  at  40  cents 
per  gallon.  The  liquefied  gas  would  therefore  cost  $2 
per  gallon. 

73 J  pounds  of  bituminous  coal  liquefied  in  38  minutes 
18  gallons  of  gas  from  the  solution  of  aqua  ammonia  at 
23°  Baume. 

Cost  of  Distillation.      Time,  38  Minutes. 

Coal,  73|  Ibs.  at  $5  per  ton  ....  $0.18375 
One  engineer,  $5  per  day,  fireman,  $2,  (38')  .  0.36939 
Machinery,  $3  per  day 0.15831 

Cost  of  liquefying  18  gallons     ....       0.71145 

Hence,  1  gallon  would  cost  ....  0.039525 
or,  about  4  cents.  1.44  gals.  =  1  mile  will  cost  5|  cents. 

This  estimate,  based  on  time  38  minutes,  assumes 
proportion  of  continuous  operation  for  the  whole  day. 
Any  intermission  would  add  to  the  cost,  and  the  cost,  as 
will  be  seen,  is  very  largely  in  excess  of  the  cost  of  com- 
pressed air  per  mile  run. 


AMMONIA  MOTOR.  25 

ESTIMATE  FOR  EUNNING  25  CARS  95  MILES  EACH 
PER  DAY. 

MADE    BY    COMMITTEE. 

Cost  of  making  3410  gallons  of  liquefied  ammonia  for 
25  cars,  running  2368  miles  per  day  :— 

Interest  on  plant,  $15,000,  at  20  per  cent.  . 
Interest  on  ammonia,  $864,  at  8  per  cent.  . 
Loss  of  ammonia,  $864,  at  25  per  cent. 

Coal,  4.64  tons,  $5 

Labor  . 


One  car  per  day  will  cost      ..... 

One  mile  will  cost         ...... 

or,  nearly  2  cents  per  mile. 

Observation. — This  sum  of  2  cents  per  car  will  repre- 
sent the  cost  of  fuel  only,  and  was  based  on  the  data 
furnished  by  the  tests  made  by  the  committee,  but  Dr. 
Lamm  states,  on  page  1 5  of  his  report,  that  the  engine 
used  on  the  car  was  two  horse-power.  This  was  probably 
an  under-estimate,  although  the  motor  was  no  doubt  a 
very  small  affair.  An  ordinary  street  steam  motor 
should  develop  from  15  to  20  horse-power.  2  cents  for 
2  horse-power  of  the  motor  would  be  very  nearly  as  ex- 
pensive as  horse-power. 

If,  as  stated,  it  required  1.44  gallons  of  liquid  ammo- 
nia to  run  the  car  one  mile,  and  the  cost  of  distillation 
was  4  cents  per  gallon,  then  the  cost  of  ammonia  would 
be  5.76  cents  per  mile,  instead  of  2  cents.  The  2  cent 
estimate  was  made  upon  hypothetical  data,  and  the  5.76 
cents  per  mile  was  for  a  2  horse-power  engine.  These 


2G  STREET   RAILWAY   MOTORS. 

estimates  cannot  be  relied  upon  as  a  basis  for  calculation 
of  expenses  on  a  large  plant. 

These  tests  must  have  been  made  under  very  unfavor- 
able conditions  in  regard  to  track  and  machinery,  and 
could  not  have  exhibited  the  full  economic  power  of 
ammonia. 

Another  estimate  of  the  cost  per  mile  run  will  be 
based  upon  the  actual  performance  of  the  Pneumatic 
Motor,  assuming  that  a  cubic  foot  of  ammonia  gas,  at  a 
given  pressure,  will  produce  an  equivalent  mechanical 
effect  to  a  cubic  foot  of  air  under  the  same  pressure. 

It  has  been  ascertained  that  720  cubic  feet  of  free  air 
compressed  to  10  atmospheres  will  run  a  motor  one 
mile.  720  cubic  feet  of  free  air  =  72  cubic  feet  at  10 
atmospheres. 

1  cubic  foot  of  liquid  ammonia  =  7J  gallons,  at  4 
cents  per  gallon  for  distillation  costs  30  cents,  and  yields 
639  cubic  feet  of  gas  under  10  atmospheres  pressure. 

The  cost  of  one  mile,  72  cubic  feet  =  30  x  Jfo  = 
3.4  cents. 

This  allows  for  no  losses.  It  is  possible  that  4  cents 
would  cover  the  expense.  This  is  a  little  below  steam, 
which  was  estimated  at  4.2  cents  per  mile  run  for  fuel 
only. 

The  Ammonia  Motor  has  been  revived  by  a  New 
Jersey  company  operating  under  new  patents.  The 
writer  called  at  the  office  of  the  company  in  New  York, 
and  was  very  courteously  received  by  the  treasurer,  who 
referred  him  to  the  draftsman  at  the  power-station  for 
detailed  information  in  regard  to  plans  and  principle  of 
operation.  The  motor  was  not  ready  for  exhibition,  but 
the  plans  were  shown  of  a  compact,  well-arranged  ma- 


AMMONIA   MOTOR.  27 

chine  for  an  independent  motor  of  capacity  sufficient  for 
one  or  two  cars,  the  dimensions  of  which  were  given  as 
follows : — 

Size— Height,  5'  6".    Length,  9  feet.    Width,  6  feet, 

Weight,  3  tons.     Horse-power,  25. 

Tractive  force,  1300  pounds.  Capacity  for  liquid 
ammonia,  44  gallons.  Capacity  for  water,  180  gallons. 
Driving-wheels,  2  feet  diameter.  Outside  connections. 

Motor  calculated  to  run  14  miles  with  one  charge. 
Speed,  6  miles  per  hour.  Cost  of  motor  as  stated  at 
office,  $3200 ;  at  power-station,  $2300. 

To  run  1  mile  with  8  tons  load  will  require  3  gallons 
of  anhydrous  ammonia. 

The  plant  to  redistill  400  gallons  in  10  hours  costs 
$3500.  As  this  apparatus  may  be  considered  as  still  in 
the  experimental  stage,  no  data  for  estimates  have  been 
given.  If  the  cost  of  redistillation  should  be  as  great  as 
in  the  New  Orleans  tests  the  cost  per  mile  run  would  be 
excessive,  amounting  to  12  cents,  but  it  is  probable  that 
this  would  be  greatly  reduced,  and  the  company  claims 
the  ability  to  redistill  the  ammonia  at  a  cost  of  1  cent 
per  gallon,  or  J  the  cost  at  New  Orleans. 

The  claims  of  the  company  are:  Great  economy  as 
compared  with  horse,  trolley,  or  cable  system,  both  in 
plant  and  in  operation,  which  claims  are  probably  well 
founded ;  also,  ability  to  run  1  mile  with  3  gallons  of 
anhydrous  ammonia.  Pressure,  150  pounds  per  square 
inch  ;  wastage,  10  per  cent. 

A  16-foot  car  can  run  25  miles  before  recharging. 
Cost  of  preparing  the  ammonia,  1  cent  per  mile.  Total 
of  all  operating  expenses,  7.68  cents  per  car-mile. 

The  above  statements  are  supported  by  record  of  tests 


28  STREET    RAILWAY    MOTORS. 

made  at  Jackson  Park,  Chicago,  April,  1892,  and  are 
given  as  the  claims  of  the  parties  interested.  The 
writer  had  no  time  or  opportunity  for  verification  of 
these  claims,  and  no  information  as  to  the  dimensions 
and  weight  of  the  motor  in  which  the  tests  were  made. 

From  the  data  given  in  the  foregoing  pages  in  regard 
to  the  ammonia  motor,  and  the  principles  upon  which  it 
operates,  the  reader  can  form  his  own  opinions  as  to  the 
probability  of  results  verifying  the  claims  that  have 
been  advanced. 


IV. 

THE   HOT-WATER  MOTOR. 

THIS  motor,  otherwise  known  as  the  fireless  locomo- 
tive, was  the  successor  of  the  ammonia  engine,  and  was 
used  for  some  years  on  the  street  railroads  of  New  Or- 
leans under  the  name  of  the  Angomar  Motor. 

The  efficacy  of  this  motor  depends  upon  the  great 
capacity  for  heat  of  water,  in  consequence  of  which  it 
is  claimed  that  a  sufficient  quantity  of  energy  can  be 
stored  in  a  reservoir  to  suffice  for  a  run  of  ordinary 
length. 

Under  the  normal  pressure  of  the  atmosphere,  water 
boils  at  212°  Fahrenheit;  but  the  boiling-point  may  be 
reduced  or  elevated  by  a  variation  of  pressure,  and 
where  pressure  is  reduced,  the  excess  above  the  tem- 
perature corresponding  to  the  reduced  pressure  is  con- 
verted into  steam  at  the  same  temperature  with  the 
pressure  due  thereto. 


THE    HOT-WATER    MOTOR. 


29 


The  following  table  gives  the  absolute  pressures,  in- 
cluding the  pressure  of  the  atmosphere  and  the  Fahren- 
heit temperatures  corresponding  thereto  : — 


p. 

T. 

P. 

T. 

P. 

T. 

14.7 

212° 

145 

356° 

360 

432° 

15 

213 

150 

358 

370 

435 

20 

227 

155 

362 

380 

437 

25 

240 

160 

365 

390 

440 

30 

250 

165 

367 

400 

442 

35 

259 

170 

370 

410 

444 

40 

267 

175 

372 

420 

446 

45 

274 

180 

374 

430 

448 

50 

281 

185 

376 

440 

451 

55 

287 

1913 

378 

450 

453 

60 

293 

195 

381 

460 

455 

65 

298 

200 

383 

470 

457 

70 

303 

210 

387 

480 

459 

75 

307 

220 

390 

490 

461 

80 

312 

230 

394 

500 

463 

85 

316 

240 

398 

525 

466 

90 

320 

250 

401 

550 

471 

95 

324 

260 

404 

575 

476 

100 

328 

270 

407 

600 

480 

105 

331 

280 

411 

650 

488 

110 

335 

290 

413 

700 

495 

115 

338 

300 

416 

750 

502 

120 

341 

310 

419 

800 

508 

125 

344 

320 

422 

850 

515 

130 

347 

330 

424 

900 

521 

135 

350 

340 

427 

950 

526 

140 

353 

350 

430 

1000 

532 

The  latent  heat  of  steam  at  212°  is  967°,  making  the 
total  thermal  units  in  one  pound  of  steam,  above  zero, 
1179,  and  above  the  freezing-point,  1147,  of  Fahren- 
heit's scale.  From  this  point  the  total  units  increase 
in  a  ratio  determined  by  the  formula  of  Regnault ;  and 
the  sum  of  the  latent  and  sensible  units  is  not  a  con- 
stant quantity,  as  Watts  supposed  it  to  be,  and  which 


30  STREET   RAILWAY   MOTORS. 

opinion  was  for  a  long  time  assumed  to  be  correct. 
The  total  units  at  212°  above  zero  being  1179,  the 
increase  is  gradual  until,  at  a  temperature  of  428°,  it 
becomes  1244,  an  increase  of  65  units  in  216°.  The 
latent  heat  at  428°  is  816  units,  instead  of  967  at  212°. 

The  volume  of  steam  at  212°  is  1700  times  greater 
than  the  water  from  which  it  was  produced. 

A  pound  of  steam  at  212°,  under  a  pressure  of  14.7 
pounds  per  square  inch,  occupies  a  volume  of  26.36 
cubic  feet.  Under  any  greater  pressure  the  volume 
will  be  proportionately  reduced. 

The  specific  heat  of  water  being  unity,  steam  is  0.475. 

When  a  portion  of  water  at  a  high  temperature  is 
converted  into  steam  by  reduced  pressure,  the  remain- 
ing water  is  cooled  to  the  extent  of  the  thermal  units 
required  for  the  conversion  of  the  water  into  steam — a 
fact  that  appears  to  have  been  neglected  in  some  com- 
putations of  the  length  of  rim  of  which  the  hot  water 
or  fireless  locomotive  is  capable. 

The  following  table  gives  pressures,  volumes,  thermal 
units  above  32°,  and  latent  heat  corresponding  to  the 
temperatures  in  the  first  column  : — 


THE   HOT-WATER   MOTOR. 


31 


Temperature. 

Pressure. 

Volume  of 
1  pound. 

Total  thermal 
units  above  32°. 

Latent 
thermal  units. 

212 

14.7 

26.36 

1147 

967 

221 

17.5 

22.34 

1149 

960 

230 

20.8 

19.03 

1152 

954 

239 

24.5 

16.28 

1155 

948 

248 

28.83 

14.00 

1158 

942 

257 

33.71 

12.09 

1160 

935 

266 

39.25 

10.48 

1163 

929 

275 

45.49 

9.12 

1165 

922 

284 

52.52 

7.97 

1168 

916 

293 

60.40 

6.99 

1171 

910 

302 

69.21 

6.15 

1174 

904 

311 

79.03 

5.43 

1177 

898 

320 

89.86 

4.81 

1179 

891 

329 

101.9 

4.28 

1182 

885 

338 

115.1 

3.81 

1185 

879 

347 

129.8 

3.41 

1188 

.    873 

356 

145.8 

3.06 

1190 

866 

365 

163.3 

2.75 

1193 

860 

374 

182.4 

2.48 

1196 

8.04 

383 

203.3 

2.24 

1199 

848 

392 

225.9 

2.03 

1201 

841 

401 

250.3 

1.84 

1204 

835 

410 

276.9 

1.67 

1207 

829 

419 

305.5 

1.53 

1210 

823 

428 

336.3 

1.39 

1212 

816 

^'4 


As  an  illustration  of  the  use  of  this  table,  suppose  10 
pounds  of  water,  at  a  temperature  of  428°  and  pressure 
of  336  pounds  per  square  inch,  are  confined  in  a  tight 
vessel,  and  that  2  pounds  are  permitted  to  blow  off  into 
the  atmosphere. 

The  10  pounds  of  water  contain  4280  thermal  units, 
and  the  2  pounds  converted  into  steam  and  escaping 
will  remove  1934  units,  leaving  2346  units  in  the  re- 
maining 8  pounds  of  water,  or  293  units  per  pound. 
The  temperature  of  the  8  pounds  of  water  will  there- 
fore be  reduced  to  293°  from  428°,  and  the  pressure 
from  336  pounds  to  60  pounds  per  square  inch. 


34  STREET    RAILWAY    MOTORS. 

steam.  It  had  sufficient  grate  surface  to  develop  18 
to  20  horse-power  by  the  combustion  of  coal  alone  in 
the  fire-box  as  in  an  ordinary  locomotive;  and  as  the 
pressure  increased  during  the  run,  it  is  evident  that 
this  effect  could  only  be  produced  by  the  consumption 
of  coal.  The  results  furnished  no  satisfactory  test  of 
the  capacity  for  service  of  hot  water  alone.  There  can 
be  no  question  that  if  the  boiler  can  be  filled  at  the 
start  with  hot  water  under  a  working  pressure,  and 
well  protected  against  radiation,  a  smaller  quantity  of 
coal  will  be  required  for  a  run  of  moderate  length  than 
would  be  required  if  feed  water  were  admitted  cold,  and 
it  is  also  certain  that  water  can  be  heated  in  a  station- 
ary tank  more  economically  than  in  a  locomotive. 

Another  report  of  tests  of  this  same  engine,  at  another 
time  and  in  a  different  locality,  gave  a  run  of  23  miles 
with  trailer,  using  128  pounds  of  coal  in  motor  and  180 
gallons  of  water.  The  pressure  at  starting  was  175 
pounds.  After  running  3J  miles  it  was  reduced  to  155 
pounds,  and  afterwards,  at  intervals,  the  gauge  pressure 
was  150,  145,  and  155  pounds,  and  at  the  end  of  the 
run  105  pounds. 

180  gallons  of  water  =  1350  pounds  evaporated  with 
128  pounds  of  coal  gives  10J  pounds  of  water  per  pound 
of  coal.  As  the  evaporation  by  consumption  of  coal  in 
the  motor  should  be  6  pounds  per  pound  of  coal,  it 
would  leave  the  equivalent  of  4J  pounds  to  be  supplied 
in  the  hot  \vater  from  the  stationary  tank. 

The  capacity  of  the  boiler  was  given  as  262J  gallons. 

Many  of  the  statements  made  in  regard  to  the  so- 
called  fireless  locomotives  are  so  unreasonable  that  no 
attempt  will  be  made  to  criticise  them.  Of  course,  no 


THE    HOT-WATER    MOTOR.  35 

engine  can  be  called  fireless  that  has  a  fire-box,  with  20 
horse-power  for  the  combustion  of  coal,  and  in  which 
coal  is  used  to  help  the  run.  Neither  can  a  boiler 
which  is  of  ordinary  material  and  construction,  sub- 
jected to  a  pressure  of  175  pounds  or  upwards,  either 
of  water  or  steam,  be  considered  as  non-explosive.  In 
fact,  in  case  of  rupture,  a  boiler  filled  with  water  at  a 
given  pressure  would  cause  much  more  damage  than  if 
filled  with  steam  at  the  same  pressure,  for  the  steam 
liberated  from  the  water  would  be  many  times  its 
volume. 

For  the  purpose  of  comparison  with  other  motors,  it 
will  be  assumed  that  the  run  is  to  be  made  entirely  with 
hot  water;  and  as  no  data  have  been  furnished  from 
which  to  calculate  the  loss  by  radiation,  these  losses 
will  be  omitted. 

The  capacity  of  the  boiler  will  be  taken  at  300  gallons 
=  40  cubic  feet  =  2500  pounds. 

The  pressure  will  be  taken,  as  given  in  the  test,  175 
pounds  per  square  inch  effective,  or  189.7  absolute. 
Temperature,  377°  F. 

The  engine  will  be  supposed  to  run  until  the  pressure 
has  been  reduced  to  60  pounds  effective  =  74.7  pounds 
absolute.  Temperature,  307°. 

The  differences  of  temperature  available  for  motor 
work,  when  converted  into  steam,  would  be  377° — 307° 
=  70°. 

Let  x  represent  the  pounds  evaporated  to  reduce  the 
temperature  from  377°  to  307°  ;  then  2500  — x  will  be 
the  quantity  remaining  at  the  lower  temperature,  and  x 
carries  off  not  only  the  70°  of  difference,  but  also  the 
latent  heat  of  967°  ;  then  2500  X  377  =  307  (2500 


34  STREET    RAILWAY    MOTORS. 

steam.  It  had  sufficient  grate  surface  to  develop  18 
to  20  horse-power  by  the  combustion  of  coal  alone  in 
the  fire-box  as  in  an  ordinary  locomotive;  and  as  the 
pressure  increased  during  the  run,  it  is  evident  that 
this  effect  could  only  be  produced  by  the  consumption 
of  coal.  The  results  furnished  no  satisfactory  test  of 
the  capacity  for  service  of  hot  water  alone.  There  can 
be  no  question  that  if  the  boiler  can  be  filled  at  the 
start  with  hot  water  under  a  working  pressure,  and 
well  protected  against  radiation,  a  smaller  quantity  of 
coal  will  be  required  for  a  run  of  moderate  length  than 
would  be  required  if  feed  water  were  admitted  cold,  and 
it  is  also  certain  that  water  can  be  heated  in  a  station- 
ary tank  more  economically  than  in  a  locomotive. 

Another  report  of  tests  of  this  same  engine,  at  another 
time  and  in  a  different  locality,  gave  a  run  of  23  miles 
with  trailer,  using  128  pounds  of  coal  in  motor  and  180 
gallons  of  water.  The  pressure  at  starting  was  175 
pounds.  After  running  3J  miles  it  was  reduced  to  155 
pounds,  and  afterwards,  at  intervals,  the  gauge  pressure 
was  150,  145,  and  155  pounds,  and  at  the  end  of  the 
run  105  pounds. 

180  gallons  of  water  =  1350  pounds  evaporated  with 
128  pounds  of  coal  gives  10J  pounds  of  water  per  pound 
of  coal.  As  the  evaporation  by  consumption  of  coal  in 
the  motor  should  be  6  pounds  per  pound  of  coal,  it 
would  leave  the  equivalent  of  4J  pounds  to  be  supplied 
in  the  hot  water  from  the  stationary  tank. 

The  capacity  of  the  boiler  was  given  as  262J  gallons. 

Many  of  the  statements  made  in  regard  to  the  so- 
called  fireless  locomotives  are  so  unreasonable  that  no 
attempt  will  be  made  to  criticise  them.  Of  course,  no 


THE    HOT- WATER   MOTOR.  35 

engine  can  be  called  tireless  that  has  a  fire-box,  with  20 
horse-power  for  the  combustion  of  coal,  and  in  which 
coal  is  used  to  help  the  run.  Neither  can  a  boiler 
which  is  of  ordinary  material  and  construction,  sub- 
jected to  a  pressure  of  175  pounds  or  upwards,  either 
of  water  or  steam,  be  considered  as  non-explosive.  In 
fact,  in  case  of  rupture,  a  boiler  filled  with  water  at  a 
given  pressure  would  cause  much  more  damage  than  if 
filled  with  steam  at  the  same  pressure,  for  the  steam 
liberated  from  the  water  would  be  many  times  its 
volume. 

For  the  purpose  of  comparison  with  other  motors,  it 
will  be  assumed  that  the  run  is  to  be  made  entirely  with 
hot  water ;  and  as  no  data  have  been  furnished  from 
which  to  calculate  the  loss  by  radiation,  these  losses 
will  be  omitted. 

The  capacity  of  the  boiler  will  be  taken  at  300  gallons 
=  40  cubic  feet  «=  2500  pounds. 

The  pressure  will  be  taken,  as  given  in  the  test,  175 
pounds  per  square  inch  effective,  or  189.7  absolute. 
Temperature,  377°  F. 

The  engine  will  be  supposed  to  run  until  the  pressure 
has  been  reduced  to  60  pounds  effective  =  74.7  pounds 
absolute.  Temperature,  307°. 

The  differences  of  temperature  available  for  motor 
work,  when  converted  into  steam,  would  be  377° — 307° 
=  70°. 

Let  x  represent  the  pounds  evaporated  to  reduce  the 
temperature  from  377°  to  307° ;  then  2500  —x  will  be 
the  quantity  remaining  at  the  lower  temperature,  and  x 
carries  off  not  only  the  70°  of  difference,  but  also  the 
latent  heat  of  967°  ;  then  2500  X  377  =  307  (2500 


36  STREET    RAILWAY    MOTORS. 

—  x)  4-  1037  #.  Consequently  x  —  242  pounds  con- 
verted into  steam,  and  leaving  2258  pounds  in  boiler  at 
the  temperature  of  307°.  242  pounds  of  steam  at  the 
average  effective  pressure  of  43  pounds  per  square  inch 
=  7.2  cubic  feet  per  pound,  gives  1742  cubic  feet  avail- 
able for  propulsion. 

The  wheels  were  31  inches  in  diameter  or  8  feet  in 
circumference.  The  number  of  revolutions  per  mile 
would  be  660. 

The  cylinders  were  9  inches  diameter,  10  inches  stroke. 
Capacity  of  4  cylinders,  2464  cubic  inches,  or  1.4  cubic 
feet  for  each  revolution  =  1.4  X  660=  924  cubic  feet 
per  mile. 

It  would  appear,  therefore,  that  the  hot  water  alone, 
without  the  aid  of  the  fire-box,  would  not  run  the  motor 
as  much  as  2  miles,  since  the  number  of  cubic  feet  avail- 
able is  only  1742. 

It  is  unnecessary  to  pursue  the  investigation  further. 
Hot  water  alone  cannot  be  relied  upon  to  run  a  motor 
for  a  sufficient  distance  unless  supplemented  by  coal 
combustion  in  a  fire-box,  which  makes  it,  in  fact,  an 
ordinary  steam  locomotive ;  and  the  slight  saving 
effected  by  heating  the  water  in  a  stationary  tank  is 
more  than  offset  by  the  inconveniences  attending  its 
use. 

COST  OF  PLANT  AND  OF  OPERATION  BY  THE 
AMMONIA  AND  THE  HOT-WATER  MOTORS. 

No  special  estimates  are  required  on  these  motors. 
The  statement  made  by  Dr.  Lamm  and  General  Beaure- 
gard  in  reference  to  the  ammonia  motor  shows  that  it 


GAS   MOTORS.  37 

was  abandoned  by  its  inventor  and  by  the  New  Orleans 
Committee  as  less  economical  and  more  troublesome  than 
the  hot-water  motor ;  and  the  statement  in  regard  to  the 
hot-water  motor  shows  that  if  is  decidedly  inferior  to 
steam,  being  in  fact  nothing  more  nor  less  than  a  steam 
engine  in  which  the  use  of  steam  for  a  short  distance  is 
obviated  by  the  substitution  of  hot  water  in  the  boiler 
taken  from  a  stationary  tank  at  a  high  temperature. 
The  economy  cannot  be  superior  to  that  of  the  ordinary 
steam  locomotive,  and  the  manipulation  on  a  large  scale 
would  be  troublesome  and  introduce  unnecessary  com- 
plications. 


Y. 

GAS  MOTORS. 

IN  all  the  ordinary  forms  of  motors,  as  steam,  air, 
electricity,  cable,  ammonia,  or  hot  water,  the  original 
source  of  power  is  heat  developed  by  the  combustion 
of  fuel,  usually  coal  or  wood,  and  transmitted  by  various 
agencies  to  the  motor  machinery. 

In  this  transmission  losses  are  sustained  to  a  greater 
or  less  extent.  Steam  loses  by  radiation  and  condensa- 
tion ;  cable  lines  lose  sixty  per  cent,  by  friction  and  other 
resistances,  and  utilize  not  more  than  forty  per  cent,  in 
car  propulsion ;  electricity  loses  an  equally  large  per- 
centage of  the  original  power  by  resistance  of  conduc- 
tors and  machinery  ;  air  by  the  heat  generated  in  com- 
pression, which  cannot  be  utilized,  but  the  equivalent  in 
motive  energy  may  be  restored  by  reheating.  There  is 


38  STREET    RAILWAY    MOTORS. 

also  a  loss  to  a  small  extent  by  friction  of  pipes  in  trans- 
mission to  long  distances,  so  that  in  all  these  cases  only 
a  portion  of  the  thermal  units  developed  in  the  com- 
bustion of  the  fuel  can  be  actually  utilized  in  the  work 
accomplished. 

In  gas  engines  there  is  no  transmission  of  heat  from 
a  furnace  to  the  motor  cylinder  with  its  attendant  losses. 
The  combustion  is  effected  and  the  power  generated  in 
the  motor  cylinder  itself,  and  the  power  is  applied 
directly  to  the  piston  ;  in  addition  to  which,  if  the  air  is 
properly  regulated  so  as  to  admit  the  proper  proportion, 
the  combustion  can  be  perfect,  the  temperature  a  maxi- 
mum, as  also  the  expansive  force  due  thereto. 

Coal  develops  in  perfect  combustion  about  14,000 
thermal  units ;  but  in  a  locomotive  only  about  one-half, 
or  7000  units,  can  be  utilized.  The  cost  of  coal  is,  at 
4  dollars  per  ton,  2  mills  per  pound. 

Gas  engines  are  run  with  gas  or  naphtha  vapor,  yield- 
ing in  combustion  about  28,000  thermal  units  per  pound. 
The  cost  of  naphtha  is  5  cents  per  gallon.  The  specific 
gravity  is  0.848,  so  that  a  gallon  weighs  6.3  pounds,  and 
the  cost  per  pound  is  8  mills. 

As  the  cost  per  pound  of  naphtha  is  four  times  as 
great  as  the  cost  of  coal,  \vhile  the  calorific  power  is  also 
four  times  as  great,  the  cost  for  equal  units  will  be  equal. 

But  naphtha,  with  regulated  admissions  of  air  to  secure 
perfect  combustion,  has  another  advantage.  The  ther- 
mometrical  temperature  is  higher  than  with  coal,  and  as 
combustion  is  effected  inside  the  motor  cylinder,  the 
force  of  expansion  and  the  impact  upon  the  piston  are 
greater  than  could  be  secured  by  an  equal  expenditure 
of  thermal  units  in  any  other  fuel,  hydrogen  alone  ex- 
cepted ;  but  the  use  of  hydrogen  is  not  practicable. 


GAS    MOTORS.  39 

Gas  motors  have  been  in  process  of  development  for 
6  or  8  years,  and  have  now  reached  a  point  where  the 
inventors  claim  that  difficulties  have  been  overcome,  and 
that  their  efforts  and  expenditures  have  been  crowned 
with  success.  Certain  it  is  that  an  order  has  been  given 
for  20  Connelly  gas  motors  for  street  railroad  use  in 
Chicago,  and  one  of  them  was  nearly  ready  to  be  tested 
in  December,  1892.  The  writer  had  the  privilege  of 
examining  this  machine,  which  appeared  to  be  simple 
in  construction,  compact,  well  built,  and  promising  satis- 
factory results,  but  without  the  test  of  experience  in 
actual  daily  use  for  a  considerable  period  of  time,  it  is 
always  unsafe  to  predict  unqualified  success  in  any  new 
mechanical  device. 

It  is  not  to  be  expected  that  the  present  gas  motors 
will  be  found  in  practice  entirely  perfect ;  but  if  defects 
are  found,  remedies  may  be  applied.  There  seems  to  be 
a  sound  principle  that  will  in  time,  if  not  immediately, 
be  utilized,  and  there  can  be  no  question  that  no  system 
now  in  general  use  can  compare  favorably  with  the  gas 
motor  in  the  economy  of  fuel  required  for  propulsion  of 
a  given  weight  for  a  given  distance,  within  the  limits  of 
street  car  service.  Compressed  air  is  the  only  power 
that  can  secure  equal  or  superior  economy ;  but  this  power 
is  not  in  use  for  motor  purposes  except  in  Europe,  where 
the  results  are  very  satisfactory,  even  with  a  motor  that 
admits  of  considerable  improvement  in  mechanical  details. 

DESCRIPTION  OF  THE  CONNELLY  GAS  MOTOR. 

This  is  a  gas  motor  carrying  its  own  store  of  fuel  for 
a  day's  run,  and  the  fuel  used  is  the  heaviest  grade  of 


40  STREET   RAILWAY   MOTORS. 

naphtha,  which  will  not  vaporize  at  the  temperature  of 
the  atmosphere.  It  is  carried  in  a  closed  tank,  which  is 
again  inclosed  in  a  radiator  filled  with  hot  water  con- 
stantly furnished  by  the  engine  cylinder.  The  radiator 
performs  important  double  service,  cooling  the  cylinders 
of  the  engine  and  warming  the  carburetter.  The  circu- 
lation of  the  water  from  the  cylinder  to  the  radiator  and 
return  is  continuous.  The  inner  vessel  or  carburetter  is 
filled  with  an  absorbent  material,  which  absorbs  the 
charge  and  leaves  no  liquid  to  be  lost  should  a  leak 
occur.  Air  is  drawn  automatically  through  the  ab- 
sorbent material,  thoroughly  carburetted,  and  supplied 
to  the  engine  in  exact  proportion  to  the  power  required. 
There  is  not  the  least  element  of  danger  attending  the 
operation  of  this  system.  The  gas  is  ignited  by  an 
electric  spark. 

The  principle  of  all  gas  engines  is  speed ;  their  speed 
cannot  be  varied  like  the  steam  engine,  but  they  must 
run  at  a  nearly  uniform  rate  ;  therefore  special  mechanism 
w'as  required  for  transmitting  power  to  the  axle  at  any 
desired  rate  of  speed.  It  was  absolutely  essential  to 
complete  success  that  this  should  be  accomplished,  and 
in  such  a  manner  that  the  speed  of  the  car  could  be 
varied  at  will  of  the  driver  by  moving  a  single  lever. 

The  mechanism  employed  for  this  important  service 
is  positive  in  action,  noiseless,  and  durable.  The  wear- 
ing parts  are  easily,  quickly,  and  cheaply  replaced.  It 
prevents  giving  shock  or  jar  to  the  car  wrhen  starting, 
and,  above  all  other  advantages,  transmits  maximum 
power  when  driving  a  car  at  minimum  rate  of  speed. 

In  the  transmission  of  power  by  friction,  it  is  neces- 
sary that  the  contact  pressure  should  vary  in  proportion 


GAS    MOTORS.  41 

with  the  power  transmitted.  This  is  accomplished  auto- 
matically by  means  of  a  right  and  left  screw  nut,  ope- 
rated by  an  eccentric  extension  of  the  hand  lever,  so  that 
any  movement  of  the  lever  in  either  direction,  to  vary 
the  speed,  changes  the  pressure  of  contact  correspond- 
ingly, thus  securing  maximum  pressure  on  grades  or 
curves,  and  minimum  when  running  at  full  speed. 
This  is  one  of  the  most  important  features  of  the  de- 
vice, as  it  would  be  impracticable  to  run  at  full  speed 
with  the  same  contact  pressure  that  is  required  when 
starting  on  grades  or  curves. 

The  above  brief  description  has  been  furnished  by 
the  inventor. 

COST  OF  OPERATION. 

It  is  claimed  by  parties  interested  that  the  cost  of 
operating  this  motor  per  day  (14  hours),  ninety  miles 
each,  is  as  follows  : — 

Cents. 
Fuel,  14  gallons  naphtha,  5  cts.         .         .         ...        .     .70 

Lubrication        .'       .         .  .         .         .         .     .10 

Care  (one  engineer  to  10  motors)       ....     .30 

Repairs      .........     .30 

Total  cost  per  day       ...         .         .         .  1.40 

Or  1T5^-  cents  per  car-mile,  not  including  driver  or 
conductor. 

The  motors  are  proposed  of  two  forms.  One  an  in- 
dependent motor  designed  for  use  on  city  roads  where 
conductors  are  employed.  These  are  independent  motors, 
eight  feet  long,  the  driver  standing  in  the  centre  and  ope- 
rating the  motor  in  either  direction  without  changing  his 
position.  The  weight  is  5800  pounds,  and  it  is  said  to  be 


42  STREET    RAILWAY    MOTORS. 

capable  of  hauling  one  standard  16-foot  car  heavily 
loaded  up  grades  of  5  per  cent.  On  grades  not  ex- 
ceeding 2  per  cent,  it  can  easily  handle  2  cars.  The 
maximum  speed  attainable  is  12  miles  per  hour,  but  the 
gearing  can  be  changed  to  secure  a  speed  of  16  miles 
per  hour  where  such  speed  would  be  allowed  by  the 
authorities. 

The  cost  of  this  motor  is  given  at  $2500. 

The  combination  motor  has  an  upper  deck,  and  can 
be  operated  with  or  without  conductor;  designed  for 
suburban  roads.  The  machinery  occupies  6  feet  of  the 
forward  end,  leaving  room  inside  for  14  passengers  and 
for  20  on  the  outside.  The  combination  motor  can  haul 
a  trailer  in  addition  on  roads  of  2  per  cent,  grades. 

As  the  gas  motor  has  not  yet  passed  the  experimental 
stage,  it  would  be  rash  to  assert  that  all  expectations  and 
promises  can  at  once  be  realized.  That  there  is  a  future 
for  this  system  seems  probable,  but  difficulties  will  no 
doubt  be  experienced.  The  charge  of  air  in  proportion 
to  naphtha  vapor  must  be  accurately  determined  and 
automatically  regulated  to  admit  the  proper  quantity ; 
the  electrical  apparatus  must  produce  the  spark  for 
ignition  at  the  proper  moment ;  the  circulation  from 
the  cylinders  to  the  carburetter  must  be  constant,  regu- 
lar, and  of  the  proper  temperature  for  vaporization.  If 
the  engine  should  stop  for  a  time  and  the  water  cool, 
there  will  be  delay  in  starting,  unless  the  water  can  be 
discharged  and  the  space  occupied  by  it  refilled  with 
hot  water  from  a  stationary  tank  so  as  to  secure  without 
serious  delay  the  temperature  necessary  for  the  evapo- 
ration of  the  naphtha.  If  stopped  on  the  track  by 
blockades  or  other  causes,  the  machinery  must  be 


GAS    MOTORS.  43 

thrown  out  of  gear,  but  the  engine  kept  running  to 
maintain  the  circulation  and  prevent  cooling,  and  this 
will  add  to  the  consumption  of  fuel,  the  estimate  having 
been  made  on  the  supposition  of  constant  movement. 
The  friction  of  contact  with  the  driving  disk  must  be 
sufficient  to  overcome  resistances  without  stopping. 

Where  a  very  large  plant  is  required,  it  may  possibly 
be  found  advantageous  to  erect  apparatus  to  manu- 
facture gas  and  use  it  compressed  in  iron  cylinders  in- 
stead of  the  carburetter,  in  order  to  reduce  the  delays  at 
starting  to  a  minimum. 

The  best  that  can  be  said  of  gas  motors  at  the  present 
time  is  that  they  promise  well  in  the  future ;  but  actual  use 
on  a  scale  of  considerable  magnitude  will  be  required  to  de- 
velop defects,  inconveniences,  and  objections,  if  any  exist, 
and  to  inspire  confidence  in  their  economy  and  efficiency. 

Taking  the  data  furnished  by  the  patentee,  which  is 
14  gallons  of  naphtha  for  a  run  of  14  hours  in  an  inde- 
pendent motor  of  5800  pounds,  and  assuming  that  the 
consumption  of  fuel  must  be  in  proportion  to  the  weight 
of  the  train  carried,  and  also  that  a  trail-car  of  5  tons  or 
10,000  pounds  must  be  carried  in  addition  to  the  motor, 
the  weight  of  the  train  would  be  nearly  3  times  as  much 
as  the  motor  itself,  and  the  consumption  of  naphtha  for 
14  miles  =  42  gallons,  if  the  14  gallons  were  required 
for  the  motor  alone.  It  is  claimed,  in  the  description 
of  the  Connelly  gas  motor,  that  it  is  capable  of  haul- 
ing a  passenger  car  in  addition ;  but  it  is  not  stated  that 
this  work  can  be  done  without  an  additional  consump- 
tion of  fuel ;  but  even  assuming  that  the  1 4  gallons  of 
naphtha  will  carry  both  the  motor  and  car  a  distance  of 
84  miles  at  6  miles  per  hour,  the  cost  of  fuel  would  be 


44  STREET   RAILWAY    MOTORS. 

8J  mills  per  mile,  which  is  more  than  the  cost  of  fuel 
alone  for  the  compressed  air  motor. 

In  addition  to  this,  it  must  be  observed  that  the  gas 
engine  must  continue  to  run,  with  the  machinery  out  of 
gear,  when  the  motor  is  standing  and  making  no  mile- 
age ;  also  that  house-room  must  be  provided  for  both 
motors  and  cars,  as  in  the  case  of  steam,  which  will  in- 
crease the  investment  in  real  estate  and  the  interest  on 
plant. 


VI. 

THE    PNEUMATIC    OR    COMPRESSED    AIR    MOTOR. 

AFTER  an  extended  investigation,  commenced  in  1879 
and  continued  recently,  with  a  long  interval  for  observa- 
tion of  other  systems,  the  writer  is  confirmed  in  his  orig- 
inal conclusion  that,  for  the  operation  of  city  and  sub- 
urban roads — whether  surface,  elevated,  or  underground 
— no  other  motive  power  can  compare  favorably  with 
compressed  air,  either  in  cost  of  plant,  economy  of  ope- 
ration, freedom  from  all  objections,  or  the  possession  of 
incidental  advantages. 

Those  who  have  not  examined  the  subject  almost  in- 
variably object  that  double  the  power  is  required  to 
compress  air  that  can  be  utilized  in  actual  work  from 
the  air  where  compressed,  and  assume  a  necessary  serious 
loss. 

It  may  be  true  that  double  the  power  may  be  re- 
quired ;  but  suppose  the  air  is  compressed  by  a  water- 
power,  otherwise  unemployed,  that  costs  nothing  except 
the  first  outlay  for  the  machinery  for  its  utilization  : 


PNEUMATIC   OR   COMPRESSED    AIR    MOTOR.  45 

might  not  the  power  be  cheaper  than  steam,  even  if 
only  10  per  cent,  could  be  utilized  ? 

The  actual  facts  are  that  air  can  be  compressed  by  the 
use  of  the  best  compound  expansion  stationary  engines 
in  which  double  the  useful  effect  can  be  secured  per 
pound  of  coal  as  compared  with  steam  motors.  This 
alone  would  at  once  place  air  on  a  par  with  steam ;  but 
in  stationary  engines  a  quality  of  coal  can  be  used  that 
costs  less  than  half  as  much  as  the  coal  required  for 
locomotives,  and  this  raises  the  economy  of  air  to  double 
that  of  steam  in  small  motors. 

But  this  is  not  all.  It  has  been  proven  by  repeated 
tests,  both  in  Europe  and  America,  that  the  simple  de- 
vice of  passing  the  air  through  a  small  tank  of  hot  water 
before  admission  to  the  motor  cylinders  again  doubles 
the  useful  effect,  and  at  the  same  time  prevents  all  in- 
convenience from  the  production  of  frost  at  the  exhaust, 
and  this  makes  the  economy  4  to  1  as  compared  with 
steam,  the  cost  of  reheating  being  merely  nominal. 

In  fact,  air  is  the  cheapest  power  that  can  be  used  for 
the  operation  of  street  railways,  and  it  is  one  against 
which  none  of  the  objections  that  apply  to  other  sys- 
tems can  be  urged.  Why  capitalists  and  engineers  have 
neglected  it  so  long  is  beyond  comprehension.  It  can 
only  be  explained  upon  the  ground  of  ignorance  of  facts 
from  failure  to  investigate. 

Air  can  be  transmitted  to  long  distances  without  any 
loss  by  condensation  or  radiation,  as  with  steam ;  and 
the  loss  by  friction,  in  pipes  of  proper  diameter,  is  in- 
considerable, even  at  a  distance  of  miles. 

The  importance  of  air  as  a  motive  power  for  city  rail- 
roads demands  a  careful  consideration  of  its  claims. 


46  STEEET  RAILWAY  MOTORS. 

PROPERTIES  OF  AIR. 

Air  is  composed  of  about  23  parts  by  weight  of  oxygen 
and  77  parts  of  nitrogen. 

By  volume  the  proportions  are  21  of  oxygen  to  79 
of  nitrogen. 

At  a  temperature  of  60°  F.,  its  weight  is  -g-j^-  that  of 
water  ess  0.0765  Ib.  per  cubic  foot. 

At  a  temperature  of  32°  12.433  cubic  feet  =  1  pound. 

The  specific  heat  of  air  at  constant  pressure  and  with 
increasing  volume  is  0.23/7,  water  being  1. 

In  doubling  the  volume  of  air  the  units  of  heat  ex- 
•pended  are,  as  given  by  Clark,  117.18  (other  authorities, 
115.8). 

If  the  temperature  be  doubled  without  adding  to  the 
volume,  the  units  expended  will  be  83.22.  To  double 
the  volume  in  addition  requires  33.96.  Total,  117.18. 

The  specific  heat  of  air  in  raising  temperature  without 
increase  of  volume  is  0.1688. 

In  compressing  air  from  a  tempe^ture  of  60°  to  one- 
half  its  volume  under  an  effective  pressure  of  15  Ibs.  to 
the  square  inch  the  temperature  will  be  raised  to  177°, 
and  the  increment  of  temperature  will  be  117°.  But 
in  continued  compression  to  30,  45,  60,  75,  90,  105, 
and  120  pounds  the  temperatures  are  successively  255°, 
317°,  369°,  416°,  455°,  490°,  and  524°,  and  the  suc- 
cessive increments  77°,  62°,  52°,  47°,  39°,  35°,  34°. 

The  capacity  of  air  for  holding  moisture  is  affected  by 
its  volume  and  temperature.,  but  apparently  not  by  its 
density.  It  appears  from  observations  made  by  manu- 
facturers of  compressed  plant  that  air  compressed  to  50 
atmospheres  contains  no  more  water  than  air  at  the  same 


PNEUMATIC    OR   COMPRESSED    AIR    MOTOR.          47 

temperature  under  one  atmosphere,  consequently  f  |  of 
the  water  is  removed  during  compression,  and  the  air 
becomes  so  dry  that  no  frost  can  be  formed  in  the  ex- 
haust. Even  when  air  is  cooled  by  passing  through 
water  no  additional  quantity  of  moisture  can  be  taken 
up.  The  compressor  used  on  the  Second  Avenue  Rail- 
road in  1879  cooled  the  air  by  passing  it  through  a  tank 
of  water  under  pressure,  yet  no  frost  was  formed  at  the 
exhaust.  It  is  now  considered  preferable,  in  the  most 
improved  construction,  to  cool  the  air  without  direct  con- 
tact with  water. 

As  every  thermal  unit  is  equivalent  to  772  pounds* 
raised  one  foot,  it  is  evident  that  if  air  could  be  c 
pressed  without  elevation  of  temperature  and  loss 
heat  in  cooling  much  would  be  gained.  Something  has 
been  accomplished  in  this  direction,  but  complete  iso- 
thermal compression  is  unattainable.  Adiabatic  compres- 
sion, or  compression  attended  by  evolution  of  heat,  is 
alone  possible ;  but  at  high  pressures  the  loss  is  propor- 
tionately less,  as  has  been  shown,  and  the  storage  capacity 
of  reservoirs  is,  by  increased  pressure,  increased  for  longer 
runs. 

It  was  observed  by  Mr.  G.  H.  Reynolds,  of  the  Dela- 
mater  Works,  that  the  heat  liberated  in  proportion  to 
the  power  secured  was  much  less  at  high  than  at  low 
pressures.  Satisfactory  explanation  can  perhaps  be 
given.  Imagine  a  vessel  containing  one  pound  of  air 
at  ordinary  tension  13  cubic  feet,  the  base  one  square 
foot  and  height  13  feet.  If,  by  means  of  a  piston,  this 
air  should  be  forced  into  one-half  the  space,  or  6J  feet, 
the  pressure  would  be  increased  to  30  pounds,  and  the 
work  done  would  be  21,528  foot-pounds.  One  pound 


48  STREET    RAILWAY    MOTORS. 

of  water  raised  1°  is  equivalent  to  772  foot-pounds,  and 
as  the  specific  heat  of  air  is  0.238,  772  x  0.238  =  184, 
the  foot-pounds  expended  in  heating  1  pound  of  air  1°. 
Then  21,528  -*- 184  =  1 16°  =  the  heat  liberated  in  com- 
pressing one  pound  of  air  into  half  its  volume. 

Now  suppose  the  6J  cubic  feet  of  air  should  be  again 
compressed  one-half,  or  to  3J,  the  final  pressure  would 
be  60  pounds,  and  the  space  3J  feet,  and  the  work 
21,528  foot-pounds  as  before,  representing  116°  of  heat. 
But  with  these  116°  of  heat  the  pressure  has  been  in- 
creased from  2  atmospheres  to  4,  and  in  like  manner 
from  4  to  8,  from  8  to  16,  and  from  16  to  32,  would 
each  require  but  116°,  and  at  the  end  16  atmospheres 
of  additional  pressure  have  liberated  only  as  much  heat 
as  one  atmosphere  at  the  commencement;  assuming 
that  the  heat  when  liberated  has  been  absorbed  so  as  to 
secure  isothermal  contraction  of  volume. 

It  must  be  remembered,  however,  that  if  the  pressure 
should  be  increased  to  16  atmospheres,  the  volume  would 
be  diminished  to  y1^,  and  if  the  air  should  be  used  at  full 
pressure  throughout  the  stroke  of  a  piston  no  advantage 
would  be  gained.  Very  high  pressures  are,  however, 
always  used  expansively,  and  if  air  at  500  pounds 
should  be  cut  off  at  T*g  of  the  stroke,  the  gain  over  an 
equal  weight  of  air  at  250  pounds  cut  off  at  J-  would 
be  32  per  cent. 

Where  temperature  is  considered,  the  results  are  quite 
different.  The  tables  for  adiabatic  compression  give 
from  one  atmosphere  to  two,  an  increase  per  one  atmos- 
phere of  115.8°.  At  8  atmospheres  the  increase  is 
36.1,  at  10  atmospheres  30°,  at  15  atmospheres  25.4°, 
and  at  25  atmospheres  16.7°  per  atmosphere:  showing 


PNEUMATIC   OR   COMPRESSED   AIR   MOTOR.          49 

that  the  increase  of  temperature  daring  compression  is 
greatest  at  low  pressures. 

The  largely  extended  use  of  compressed  air  for  engi- 
neering purposes  has  led  to  great  improvements  in  air 
compressors,  and  responsible  parties  can  now  be  found 
to  furnish  plant  and  guarantee  results  at  a  very  mode- 
rate cost,  thus  removing  any  element  of  uncertainty.  It 
is  claimed  that  the  best  compressors  now  constructed  give 
a  result  about  midway  between  the  isothermal  and  the 
adiabatic,  and  the  net  loss  of  power  due  to  clearance  is 
so  small  as  to  be  practically  unworthy  of  consideration. 

The  losses  by  transmission  of  air  through  pipes  are 
comparatively  slight.  It  has  been  stated  by  competent 
authority  that  there  is  not  a  properly  designed  com- 
pressed air  installation  to-day  that  loses  over  5  per  cent, 
by  transmission  alone.  The  largest  compressed  air 
power  plant  in  America  is  that  at  the  Chapin  mines  in 
Michigan,  where  the  power  is  generated  at  the  Quin- 
nesec  Falls,  and  transmitted  3  miles.  The  loss  of  pres- 
sure as  shown  by  the  gauge  is  only  2  pounds.  At  the 
Jeddo  Tunnel  near  Hazelton,  air  under  60  pounds  pres- 
sure was  conveyed  860  feet,  and  the  gauges  indicated  no 
difference  of  pressure.  The  pipe  in  this  case  being  5f 
inches  in  diameter,  was  very  large  for  the  quantity  of 
air  used. 

The  losses  in  compressed  air,  it  is  said,  may  be  reduced 
to  20  per  cent,  of  the  power  used  by  combining  the 
best  system  of  reheating  with  the  best  air  compressors. 

In  France,  England,  and  Germany  there  have  been 
erected  during  recent  years  large  compressed  air  instal- 
lations.    In  Paris  about  25,000  horse-power  is  trans- 
mitted over  the  city,  and  is  used  to  drive  engines  and 
4 


50  STKEET    RAILWAY    MOTORS. 

for  many  other  purposes.  A  small  motor  4  miles  from 
the  central  station  can  indicate  in  round  numbers  10 
H.  P.  for  20  H.  P.  at  the  station  itself,  and  by  combin- 
ing the  American  Compound  Condensing  Corliss  Air 
Compressor  with  an  efficient  and  economical  reheating 
apparatus,  and  Corliss  or  other  economical  engines,  an 
increase  of  efficiency  of  50  per  cent,  may  reasonably  be 
expected. 

The  air  used  in  Paris  is  about  11  cubic  feet  of  free 
air  per  minute  per  indicated  horse-power.  The  ordinary 
practice  in  America  with  cold  air  is  from  15  to  25  cubic 
feet  per  minute  per  indicated  H.  P.  The  engines  in 
France  were  found  to  consume  about  15  cubic  feet  of 
air  per  minute  per  H.  P.  without  reheating. 

The  amount  of  coal  consumed  in  Paris  during  reheat- 
ing is  trifling.  With  the  reheaters  commonly  em- 
ployed, it  amounts  to  from  one  to  two  cents  per  horse- 
power per  day,  and  these  figures,  it  is  said,  can  be  reduced 
considerably  by  a  more  economical  system  of  reheating. 

In  the  transmission  of  air  through  pipes,  the  loss  of 
pressure  can  be  very  conveniently  and  accurately  calcu- 
lated by  taking  the  loss  for  a  given  length  and  diameter 
of  pipe  and  initial  velocity,  and  determining  the  loss  for 
any  other  velocity,  diameter,  and  length,  by  a  simple 
proportion,  observing  that  the  loss  of  pressure  is — 

Directly  as  the  length  of  pipe  and  square  of  the  initial 
velocity. 

The  friction  in  1  mile  of  6-inch  pipe,  with  an  initial 
velocity  of  20  feet  per  second,  is  5.1  pounds  per  square 
inch. 

Suppose  1500  cubic  feet  of  free  air  per  minute,  under 
500  pounds  pressure  or  34  atmospheres,  are  to  be  carried 
1  mile.  What  will  be  the  loss  by  friction  ? 


PNEUMATIC   OR   COMPRESSED    AIR   MOTOR.  51 

1500 

In  this  case,  the  initial  volume  will   be  =»  44 

34 

cubic  feet.  44  cubic  feet  per  minute  =  0.74  cubic  foot 
per  second. 

A  pipe  6  inches  in  diameter  has  an  area  in  square  feet 
of  0.127. 

0.74  -f-  0.127  =  6  feet  per  second,  nearly. 

62 

Then  5.1  x  -  —  =  0.457  pound,  a  very  inconsider- 
able loss  in  a  distance  of  1  mile,  and  the  loss  in  10 
miles  would  be  only  4J  pounds. 

In  this  calculation  the  initial  density  of  the  air  is  not 
taken  into  consideration,  and  it  does  not  affect  the  result 
with  an  elastic  fluid  of  uniform  density ;  but  a  general 
formula,  applicable  to  all  elastic  fluids,  must  recognize 
density,  and  the  loss  of  pressure  in  elastic  fluids  of  dif- 
ferent densities,  other  conditions  the  same,  will  be  directly 
as  the  densities.  The  loss  of  pressure,  for  example,  in 
the  transmission  of  steam  through  pipes  will  be  about 
half  as  great  as  with  air,  other  conditions,  except  density, 
being  the  same. 

The  cost  of  hydraulic  pipes  to  resist  high  pressures 
has,  January,  1893,  been  obtained  from  manufacturers. 

Cents. 

3-inch  pipe  per  lineal  foot    .         .         *        -.    >     .      20.82 

.    .    .         .      24.61 

29.26 

35.25 


43.51 

54.87 

64.84 

84.90 

115.78 


52  STREET    RAILWAY    MOTORS. 

The  quantity  of  air  required  for  running  an  ordinary 
street  motor  of  about  18  or  20  horse-power  capacity,  for 
a  distance  of  1  mile  upon  an  ordinary  street  railway,  has 
been  positively  and  accurately  determined  by  several 
months'  service  of  the  Hardie  Motor  on  the  Second 
Avenue  Railroad  in  New  York  in  1879,  and  also  by 
the  experience  in  France  and  England.  On  this  im- 
portant point  there  can  be  no  mistake,  and  ample  evi- 
dence can  be  furnished. 

The  Hardie  combined  motor  and  car,  weighing  8J 
tons,  including  passengers,  ran  9f  miles  on  a  bad  track 
on  the  Second  Avenue  Railroad.  The  pressure  at  start- 
ing was  360  pounds;  at  finish,  100  pounds  and  reser- 
voir capacity  160  cubic  feet,  giving  the  quantity  of  free 
air  at  atmospheric  pressure  expended  2.773  cubic  feet 
=  284  cubic  feet  per  motor-mile,  or  33  J  cubic  feet  per 
ton-mile. 

The  Mekarski  (French)  combined  motor  and  car, 
weighing  8  tons,  including  passengers,  ran  7f  miles  on 
a  street  tramway  with  an  expenditure  of  36J  cubic  feet 
per  ton  per  mile,  or  292  cubic  feet  per  car-mile. 

The  Beaumont  (English)  locomotive,  weighing  7 
tons,  is  claimed  by  the  inventor  to  be  capable  of  draw- 
ing a  5-ton  car  10  miles  on  a  street  tramway.  Ca- 
pacity of  reservoir,  100  cubic  feet.  Pressure  at  starting, 
1000  pounds  per  square  inch ;  at  finish,  not  stated,  but 
presumably  80  pounds.  This  gives  a  total  expenditure 
of  6.100  cubic  feet  of  free  air,  or  50  cubic  feet  per  ton 
per  mile,  or  500  cubic  feet  per  train-mile  of  motor  and 
car. 

The  Beaumont  locomotive,  of  same  capacity  and 
pressure,  but  said  to  be  10  tons,  ran  15  miles  light, 


PNEUMATIC   OR   COMPRESSED   AIR    MOTOR.  53 

and  without  stopping,  on  a  clean  steam  railway,  using 
6.100  cubic  feet  of  free  air,  or  40  cubic  feet  per  ton  per 
mile. 

The  Scott-Moncrieff  combined  motor  and  car,  weigh- 
ing 7J  tons,  is  claimed  to  have  run  7  miles  on  a  street 
tramway.  Reservoir  capacity,  150  cubic  feet.  Pressure 
at  starting,  390  pounds  (26  atmospheres);  at  finish,  not 
stated,  but  presumably  about  50  pounds,  thus  using 
3450  cubic  feet,  or  67J  cubic  feet  per  ton  per  mile,  472 
cubic  feet  per  car-mile. 

It  is  thus  seen  that  Hardie  and  Mekarski  produce  the 
best  results,  owring  to  the  more  efficient  method  of  heat- 
ing. Beaumont  heats  a  little,  and  Scott-Moncrieff  not 
at  all. 

It  thus  appears  from  all  these  statements  that  the 
Hardie  motor  gave  better  results  than  any  other, 
although  the  mechanical  work  was  defective  owing  to 
cheap  construction  without  the  usual  facilities  for  locomo- 
tive work,  and  the  runs  were  over  a  very  bad  track.  It 
is  certain  therefore  that  a  consumption  of  300  cubic  feet 
of  free  air  used  in  the  cylinders  at  a  pressure  of  56  pounds 
per  square  inch  will  suffice  to  run  the  motor  one  mile. 

The  reservoir  in  the  Hardie  motor  had  a  capacity  of 
160  cubic  feet ;  but  even  at  130  cubic  feet,  and  a  pressure 
of  34  atmospheres,  500  Ibs.  per  square  inch,  the  motor 
could  run  12  miles  and  retain  over  60  Ibs.  pressure  at 
the  end  of  the  trip. 

The  Hardie  motor  when  towing  two  cars  used  480 
cubic  feet  of  air  per  mile. 

It  has  been  found  that  whatever  may  be  the  pressure 
of  air  in  the  motor  tanks  beyond  a  certain  very  mode- 
rate excess  above  the  working  pressure,  the  additional 


54  STREET    RAILWAY    MOTORS. 

power  expended  in  compression  cannot  be  made  avail- 
able in  propulsion,  but  is  lost  in  wire  drawing  the  air 
through  the  reducing  valve  to  a  lower  pressure.  Conse- 
quently all  the  power  expended  to  secure  high  pressures 
in  the  reservoirs  serves  only  to  increase  the  tank  capacity 
and  the  length  of  run. 

To  avoid  this  loss,  compound  engines  have  been  tried, 
but  they  are  not  only  unsuited  for  small  motors  in  con- 
sequence of  complication,  but  they  have  failed  to  accom- 
plish the  object. 

Another  plan  of  utilizing  the  high  pressure  has  been 
proposed  by  allowing  it  to  escape  through  an  injector, 
and  thus  forcing  an  additional  volume  of  fresh  air  into 
the  motor  cylinders,  reducing  to  that  extent  the  draft 
upon  the  reservoir.  It  is  not  known  that  this  plan  has 
be^n  tried,  or,  if  tried,  what  has  been  the  percentage  of 
gain. 

It  is,  therefore,  an  interesting  question  to  determine 
what  is  the  actual  loss  in  high  compression  measured  by 
coal  consumption  per  mile  run. 

Assume  as  data,  therefore,  that  a  motor  reservoir  of 
130  cubic  feet  capacity  is  to  be  charged  once  in  two 
minutes  to  a  pressure  of  500  pounds,  and  determine  the 
value  of  the  coal  consumed  in  raising  the  pressure  from 
250  to  500  Ibs.  per  square  inch,  which  coal  consumption 
cannot  be  again  reproduced  in  work,  but  represents  a 
loss. 

To  obtain  130  cubic  feet  at  500  Ibs.  or  34  atmos- 
pheres, 260  cubic  feet  at  17  atmospheres  must  be  reduced 
in  volume  one-half  in  two  minutes  of  time.  In  effecting 
this  compression  a  piston  with  an  area  of  one  square 
foot,  or  144  square  inches,  must  travel  130  feet  in  two 


PNEUMATIC   OR   COMPRESSED   AIR   MOTOR.  55 

minutes,  with  a  pressure  at  the  start  of  250  pounds  per 
square  inch,  at  the  end  of  500  pounds  and  mean  of 
0.846  X  500  —  423  Ibs. 

The  amount  of  work  done  in  one  minute  is  423  X  144 

130 
X =  3,959,280    foot-pounds    per    minute  =  120 

2i 

horse-power. 

At  2J  pounds  of  coal  per  horse-power  per  hour,  the 
consumption  in  2  minutes  for  120  horse-power  would 
be  10  pounds,  and  as  this  volume  of  air  at  500  pounds 
will  run  the  motor  12  miles,  with  a  reserve  in  the  tank 
at  the  end  of  the  trip  of  20  per  cent.,  the  actual  consump- 
tion for  the  trip  of  the  coal  required  for  double  com- 
pression would  be  but  8  pounds,  costing,  at  $3  per  ton 
for  the  cheap  coal  used,  1J  mills  per  pound,  or  12  mills 
for  12  miles,  or  one  mill  per  mile  run  of  motor. 

It  appears,  therefore,  that  notwithstanding  the  fact 
that  high  pressures  cannot  be  directly  utilized  in  propul- 
sion, the  cost  of  producing  them  is  so  small,  and  the  ad- 
vantage of  increased  storage  capacity  and  increased 
length  of  run  so  great,  that  it  secures  great  economy  to 
use  them,  and  it  is  useless  to  attempt  to  employ  cumber- 
some mechanical  devices  to  save  so  inconsiderable  a  loss, 
even  if  there  was  a  prospect  of  success,  which  there  is 
not. 

If  air  at  500  pounds  could  be  applied  directly  to  the 
piston  of  the  motor-cylinders,  and  cut  off  at  one-sixteenth 
of  the  stroke,  the  weight  of  air,  or  the  quantity  at  at- 
mospheric tension,  would  be  the  same  as  if  used  at  250 
pounds  and  cut  off  at  one-eighth  ;  but  there  would  be 
a  considerable  difference  in  the  work  done,  as  will  be 
seen. 


56  STREET    RAILWAY    MOTORS. 

The  initial  pressure  being  unity,  the  average  at  y1^-  is 
0.236. 

The  initial  pressure  being  unity,  the  average  at  ^  is 
0.355. 

Then,  500  X  0.236  =  1.180. 

And,   250  x  0.355  -.  0.888. 

These  figures  are  in  proportion  to  work  done,  and  the 
difference  is  0.292,  or  32  per  cent,  in  favor  of  the  higher 
pressure  if  it  could  be  utilized. 

But  the  important  practical  question  is:  What  does  this 
difference  cost  in  money  measured  by  coal  consumed  ? 
The  data  are,  air  per  mile  300  cubic  feet,  12  miles  = 
3600  cubic  feet.  Two-minute  intervals  =  1800  cubic 
feet  per  minute.  To  compress  this  volume  requires  500 
horse-power  per  hour,  or  500  x  2J  =  1250  Ibs.  coal 
per  hour.  42  pounds  in  2  minutes  for  a  run  of  12 
mills  =  5J  mills  per  mile,  and  the  loss  by  wire  draw 
1.31  mills  per  mile. 

But  by  having  500  pounds  pressure  in  the  reservoir 
instead  of  250,  the  motor  can  run  12  miles  instead  of  6, 
and  the  cost  of  compression  from  250  pounds  to  500 
pounds  is  only  one  mill  per  mile,  as  shown  elsewhere  : 
therefore  it  is  great  economy  to  use  high  pressure,  even 
if  there  is  a  loss  at  the  reducing  valve. 

It  may  be  interesting  to  give  this  subject  further  con- 
sideration, and  in  this  connection  a  quotation  from  the 
pamphlet  of  Mr.  Potter  becomes  pertinent  as  an  intro- 
duction. Referring  to  losses,  he  remarks  : — 

By  far  the  greatest  loss  of  all  is  accounted  for  by  the 
"  wire  drawing,"  which  takes  place  in  reducing  the 
storage  pressure  to  a  practicable  working  pressure. 

Let  it  be  supposed,  for  illustration,  that  this  storage 


PNEUMATIC   OR   COMPRESSED    AIR    MOTOR.  57 

pressure  is  1000  pounds  to  the  square  inch,  and  that  it 
is  reduced  to  100  pounds  in  the  locomotive  cylinders. 
It  may  easily  be  computed  by  experts  that  there  will  be 
a  loss  in  this  case  of  over  two-thirds  of  the  power  orig- 
inally contained  in  the  air  in  its  high  pressure  state. 
Experiments  have  been  made  with  a  view  to  recovering 
this  loss  by  direct  expansion  in  the  locomotive  cylinders, 
but  they  have  utterly  failed,  as  will  now  be  made 
apparent. 

It  seems  reasonable  and  rational  to  suppose  that  this 
would  be  the  proper  way  to  overcome  the  difficulty,  pro- 
vided that  it  did  not  entail  too  much  complication  of 
machinery,  and  it  was  accordingly  in  this  manner  that 
Hardie  originally  attempted  it. 

Discarding  the  idea  of  compounding  the  cylinders  as 
impracticable,  owing  to  the  complication  necessarily  in- 
volved, and  other  considerations,  which  will  be  referred 
to  further  on,  he  designed  an  experimental  engine  having 
two  cylinders  of  equal  dimensions  and  slide-valves  as 
usual,  adding  cut-oif  valves  and  other  simple  devices 
which  experience  had  shown  to  be  essential  to  the  eco- 
nomical use  of  compressed  air.  The  slide-valves  were 
specially  designed  to  balance  the  high  pressure,  all  parts 
were  proportioned  to  bear  the  excessive  strains,  and  the 
lowest  possible  storage  pressure  for  the  air  adopted  (360 
Ibs.  per  square  inch).  Upon  trial  this  engine,  which  was 
in  the  form  of  a  combined  motor  and  car,  was  found  to 
work  exceedingly  well,  running  ten  miles  on  a  street 
tramway  with  one  charge  of  air. 

Indicated  diagrams,  taken  at  all  initial  pressures, 
showed  the  most  beautiful  and  perfect  expansion  curves  ; 
and  indeed,  the  experiment  was  regarded  as  eminently 


58  STREET    RAILWAY   MOTORS. 

satisfactory.  Mr.  Hardie,  however,  being  curious  to 
know  how  much  greater  was  the  efficiency  by  this 
method  than  by  the  use  of  a  reducing  valve,  had  one 
applied,  and  found  to  his  great  astonishment  that  the 
engine  worked  just  as  well;  that  is  to  say,  that  it  ran  as 
great  a  distance  as  before.  The  engine  was  carefully 
examined,  but  no  defects  were  found,  and  the  experi- 
ments were  repeated  with  the  same  results.  Experts 
were  consulted  to  ascertain,  if  possible,  the  reason,  and 
the  only  conclusion  arrived  at  was  that  possibly  the 
use  of  such  high  pressures  in  the  engine  cylinders 
entailed  loss  by  excessive  friction  and  leakage,  which  in 
practice  neutralized  the  theoretical  gain.  Be  that  as  it 
may,  there  was  no  disputing  the  facts,  and  Mr.  Hardie, 
therefore,  gave  it  up  and  adopted  the  reducing  valve, 
there  being  no  advantage  in  straining  the  machinery 
with  high  pressures. 

It  appears  that  Colonel  Beaumont,  in  England,  has  been 
laboring  diligently  to  effect  the  same  object  by  com- 
pounding the  engine  cylinders;  but  as  will  be  seen,  his 
experiments  led  to  the  same  practical  conclusions  as 
those  of  Mr.  Hardie.  He  begins  by  presuming  that  the 
energy  stored  in  the  high  pressure  air  is  all,  or  nearly 
all,  recoverable  by  expansion  in  the  motor  cylinders,  and 
hence  argues  that  the  only  consideration  in  fixing  the 
initial  pressure  is  that  of  conveniently  storing  the 
amount  of  power  in  a  given  space.  This,  he  says,  is 
1 00  Ibs.  per  square  inch  in  a  7-ton  motor  having  a  capacity 
of  100  cubic  feet  and  of  hauling  a  5-ton  car  10  miles  on 
a  street  tramway. 

Here  follows  a  statement  of  the  practical  disadvan- 


PNEUMATIC   OR   COMPRESSED    AIR    MOTOR.  59 

tage  of  using  compound  cylinders  upon  a  street  motor 
which  it  is  not  necessary  for  present  purposes  to  repeat. 
Proceeding  to  investigate  the  results  of  the  experi- 
ment obtained  by  Beaumont  with  such  an  engine, 
reference  is  made  to  a  paper  read  by  him  on  the  subject 
before  the  Society  of  Arts  and  published  in  the  journal 
of  the  Society  March  18,  1881.  On  page  389  there  is  a 
tabular  statement  of  experimental  data,  which  is  here 
reproduced. 

Table  of  Experimental  Data. 

Air  Pressure.  Minutes.  Pounds. 

925  Ibs.  run  1000  yards  in    9  reduced  pressure  to  805 

805    "         "                 "          9  "                 "  730 

730    "         "                "          9  "                "  660 

660    "         "                 "        13  "                 "  595 

595    "         "                 "        10  "                 "  520 

5000  yards  run.      Loss   405  Ibs.  in  50  minutes  =  3  miles  73 

yards  per  hour. 

520  Ibs.  run  1000  yards  in  10  reduced  pressure  to  435 

435    "         "                 "        10  "                 "  360 

360    "         "                 "        10  "                 "  288 

288    "         "                 "        10  "                 "  205 

4000  yards  run.     Loss  315  Ibs. 

If  instead  of  expanding  this  air  freely,  it  were  made 
to  do  useful  work,  from  1000  Ibs.  down  to  200  Ibs., 
and  then  from  200  Ibs.  to  atmospheric  pressure,  the 
work  done,  upon  the  whole,  would  reasonably  be  ex- 
pected to  be  greater  than  in  the  latter  case  alone. 
Hence,  Beaumont's  claim  to  having  accomplished  great 
results  is  readily  believed,  both  by  practical  and  scientific 
men.  That  no  such  perfection  is  actually  obtained  in 
practice,  however,  will  be  seen  from  a  careful  study  of 
the  table.  Here  let  it  be  observed  the  pressures  are 
given  at  the  beginning  and  end  of  each  1000  yards  run, 


60 


STREET   RAILWAY    MOTORS. 


the  difference  in  each  case  being  an  exact  measure  of  the 
quantity  of  air,  and  also,  when  the  pressure  is  taken 
into  account,  a  measure  of  the  energy  expended.  Now 
let  these  differences  be  noted  : — - 


First      1000  yards 

Second 

Third 

Fourth 

Fifth 

Sixth 

Seventh 

Eighth 

Ninth 


used 


120  Ib 

75 
70 
65 
75 
85 
75 
72 
83 


From  what  has  been  said  it  would  have  been  expected 
that  as  more  energy  is  stored  in  the  higher  pressures, 
these  figures  should  have  shown  a  gradual  increase, 
until  the  last  was  about  double  the  first.  Neglecting 
the  first  as  excessive  and  probably  due  to  some  special 
cause,  it  is  seen  that  the  remaining  8  trips  were  accom- 
plished on  practically  the  same  quantity  of  air  (viz.  :  an 
average  of  75  Ibs.  to  the  square  inch,  or  5  volumes  of 
the  reservoir  capacity  at  atmospheric  pressure),  but  by 
no  means  on  the  same  expenditure  of  energy ;  and  it  is 
particularly  noticeable  that  the  eighth  trip  (or  last  but 
one)  was  accomplished  on  an  expenditure  which  was  less 
than  the  average.  Hence  the  inevitable  conclusion,  that 
if  the  higher  pressures  had  been  reduced  to  the  average 
pressure  of  the  eighth  trip,  at  least  as  good  economy 
would  have  been  attained,  showing  clearly  that  Colonel 
Beaumont's  experiments  go  for  nothing  more  than  to 
confirm  Mr.  Hardie's  experience,  and  that  the  advan- 
tages claimed  for  cylinder  expansion  beyond  certain 
limits  are  mostly  theoretical. 


TESTS    OF    HAEDIE   COMPRESSED    AIR   MOTOR.       61 


VII. 

TESTS  OF  THE  HARDIE  COMPRESSED  AIR  MOTOR. 

IN  1879  the  writer  was  called  upon  to  investigate  and 
report,  as  consulting  engineer,  upon  the  practicability  and 
relative  economy  of  compressed  air  as  a  motive  power 
upon  street  railways. 

At  that  time  five  motors  had  been  constructed  for  the 
Pneumatic  Tramway  Engine  Company  and  were  in 
daily  use  upon  the  Second  Avenue  Railroad  in  New 
York,  by  consent  of  its  officers,  but  at  the  expense  of 
the  Pneumatic  Tramway  Company,  which  desired  an 
opportunity  of  giving  the  invention  a  practical  test. 

The  motors  were  constructed  upon  plans  prepared  by 
Mr.  Robert  Hardie,  a  Scotch  engineer  of  remarkable 
ability,  who  had  been  engaged  with  Scott  Moncrieff,  of 
Glasgow,  in  very  successful  experiments  in  that  city. 
Lewis  Mekarski,  of  Paris,  had  also  made  successful  ex- 
periments in  the  same  direction. 

The  motors  and  also  the  compressor  plant  were  con- 
structed at  the  Delamater  Works  in  New  York,  but  as 
this  establishment  did  not  make  a  specialty  of  locomo- 
tives and  had  not  at  that  time  the  appliances  that  were 
necessary  to  secure  the  best  results,  some  of  the  wearing 
parts  were  found  to  be  rather  soft,  a  fact  which  to  some 
extent  increased  the  cost  of  repairs,  but  did  not  discredit 
the  plans  of  construction.  There  can,  of  course,  be  no 
more  wear  on  the  rubbing  surfaces  of  a  pneumatic  motor, 


62  STREET    RAILWAY   MOTORS. 

when  properly  case-hardened,  than  on  an  ordinary 
locomotive. 

The  consideration  of  the  applicability  of  compressed 
air  as  a  motive  power  for  street  engines  was  taken  up 
with  no  bias  in  its  favor,  and  the  following  extracts 
from  the  report,  made  February  20,  1879,  will  give  the 
conclusions  reached  after  careful  investigation  of  the 
motors  in  actual  daily  use. 

In  1856,  while  engaged  in  devising  plans  for  the  con- 
struction of  the  Hoosac  Tunnel,  the  writer  had,  after 
careful  consideration,  rejected  compressed  air,  and  decided 
in  favor  of  steam  in  connection  with  a  vacuum  system 
of  ventilation,  as  more  simple,  economical,  and  effectual 
under  the  conditions  then  and  there  existing  in  regard 
to  its  use,  limited  financial  resources  for  the  purchase  of 
plant  being  an  important  consideration. 

In  any  mode  of  compressing  air  in  which  the  direct 
pressure  of  steam  is  employed,  as  in  reciprocating 
pumps,  a  cylinder  of  steam  unexpanded  and  at  maximum 
pressure  must  be  expended  to  secure  under  high  ten- 
sions a  small  fraction  of  a  cylinder  of  air  at  the  same 
tension. 

If  a  number  of  small  compressors  be  connected  with 
one  shaft  by  cranks,  at  such  angles  as  to  divide  the  cir- 
cumference equally,  the  loss  of  power  would  be  reduced, 
or  the  percentage  of  useful  effect  would  be  increased. 

Suppose,  for  the  sake  of  illustration,  that  there  were 
ten  compressors  connected  with  one  shaft,  and  that  it 
was  proposed  to  compress  the  air  to  ten  atmospheres. 
There  would  be  ten  discharges  into  the  receiver  at  each 
revolution,  each  discharge  being  one-tenth  of  a  cylinder, 


TESTS   OF    HAKDIE   COMPRESSED   AIR   MOTOR.       63 

and  the  sum  of  the  whole  equal  to  one  full  cylinder  at 
the  proposed  maximum  tension. 

The  power  exerted  in  effecting  the  compression  in 
each  cylinder  would  be  in  proportion  to  the  mean  pres- 
sure throughout  the  stroke,  if  the  air  cut  off  at  one-tenth 
were  allowed  to  expand,  which  is  3.302 ;  and  if  the  air 
was  not  used  expansively  the  theoretical  loss  without" 
allowance  for  friction  would  be  as  3.3  to  1,  and  wijfh, 
friction  fully  as  5  to  1. 

But  the  air  can  be  and  is  used  expansively,  and 
simple  device  of  a  fly-wheel,  by  which  momentum  can 
be  stored  up  and  maintain  uniformity  during  a  revolu- 
tion, secures  equally  favorable  results  with  a  small  as 
with  a  large  number  of  compressors  connected  with  a 
shaft.  There  is  no  reason  whatever  to  question  the  results 
claimed  for  the  compressors  manufactured  at  the  Dela- 
mater  works,  and  used  on  the  Second  Avenue  Railroad, 
of  50  horse-power  of  compressed  air,  capable  of  being 
fully  utilized  for  every  100  horse-power  expended  in  the 
engine  which  works  the  compressors. 

But  it  will  be  said  there  is  still  a  loss  of  one-half  as 
compared  with  steam  applied  directly.  The  answer  is, 
not  in  cost  of  power ;  and  in  this  fact  is  found  the  key 
to  the  solution  of  the  problem. 

The  minimum  of  weight  is  essential  in  a  locomo- 
tive engine.  Heavy  apparatus  for  securing  economy  of 
fuel  cannot  by  any  possibility  be  applied  to  it.  Com- 
pound and  condensing  engines  are  entirely  inadmissible 
on  wheels  of  small  motors  adapted  to  street  service,  but 
all  the  known  economies  in  engines,  regardless  of  weight, 
can  be  introduced  in  stationary  plant,  and  Corliss,  Dela- 


64  STREET    RAILWAY    MOTORS. 

mater  and  others,  now  secure  as  an  ordinary  result  a 
duty  of  one  horse-power  from  2J  pounds  of  coal. 

At  the  Holly  Works  at  Lockport,  which  claim  an  ex- 
ceptionally high  average  duty;  the  daily  evaporation  is 
nine  pounds  of  water  to  one  pound  of  coal  under  25 
pounds  pressure,  or  seven  pounds  of  coal  to  one  cubic 
foot  of  water  evaporated ;  and  in  small  boilers,  such  as 
are  used  for  heating  purposes,  the  average  evaporation 
under  ten  pounds  pressure  is  only  four  pounds  of  water 
per  one  pound  of  coal,  or  15.7  pounds  of  coal  per  cubic 
foot  of  water  evaporated. 

With  no  very  reliable  data  to  determine  the  consump- 
tion of  coal  and  evaporation  of  water  in  ordinary  street 
motors,  it  will,  no  doubt,  be  greatly  in  their  favor  to 
credit  them  with  developing  a  horse-power  with  ten 
pounds  of  coal ;  and  the  conclusion,  therefore,  is  that 
although  one- half  the  power  of  the  stationary  engine  is 
lost  in  compressing  air,  yet  the  economy  of  fuel  can  be 
made  so  great  that  a  given  amount  of  power  in  com- 
pressed air  is  secured  at  one-half  the  cost  of  the  direct 
application  of  steam  to  street  motors. 

But  this  is  not  all.  By  the  simple  device  of  heating 
the  air  by  passing  it  through  a  tank  of  water,  it  has 
been  clearly  demonstrated  as  the  result  of  constant  prac- 
tice in  Paris,  confirmed  by  recent  experiments  on  the 
Second  Avenue  Railroad,  that  capacity  for  work  is 
doubled,  or  the  gain  100  per  cent.,  making  the  economy 
of  power  as  compared  with  the  direct  application  of 
steam  to  street  motors,  measured  as  it  should  be,  by 
coal  consumed,  four  to  one  in  favor  of  compressed  air. 

Air  is  compressed  into  the  car  reservoirs  under  a  pres- 


TESTS    OF    HARDIE   COMPRESSED    AIR    MOTOR.        65 

sure  of  350  pounds  per  square  inch,  or  24  atmospheres, 
nearly. 

It  is  not  applied  directly  to  the  motor  cylinders  at 
this  pressure,  experience  having  shown  that  the  best 
practical  results  are  secured  at  16  atmospheres,  about 
240  pounds. 

But  the  air  is  not  applied  cold ;  it  is  admitted  to  a 
tank  of  water  placed  on  the  front  platform  of  the  car, 
containing  5  cubic  feet  of  water,  drawn  from  a  station- 
ary boiler,  tinder  80  pounds  pressure  and  having  a  tem- 
perature of  328°. 

If  air  is  admitted  to  the  tank  at  60°,  and  leaves  it  at 
328°,  the  increase  of  temperature  will  be  (328—60) 
268°. 

To  raise  one  pound  of  water  from  32°  to  212°,  or 
180°,  requires  as  much  heat  as  would  raise  4.27  pounds 
of  air  through  the  same  range.  The  specific  heat  of  air 
as  compared  with  water  being  as  0.2377  to  1,  one  pound 
of  air  increases  in  volume  by  heat  from  12.387  cubic 
feet  at  32°  to  19.323  cubic  feet  at  328°=6.936  cubic 
feet  increase. 

The  volume  of  air  at  24  atmospheres  being  1,  the 
volume  at  1 6  atmospheres  would  be  1.5.  If  the  volume 
of  air  at  32°  be  1,  the  volume  at  60°  will  be  1.061,  and 
at  328°  =1.59.  It  appears,  therefore,  that  in  heating  a 
given  quantity  of  dry  air  to  328°,  it  will  be  increased  in 
volume  under  constant  pressure  over  50  per  cent. 

This  expansion  is  due  simply  to  dry  air;  when  mois- 
ture is  present  to  the  point  of  saturation  the  pressures 
are  greatly  increased. 

If  the  air  at  30°  be  taken  as  unity,  dry  air  at  212° 

5 


66  STREET    RAILWAY    MOTORS. 

will  occupy  a  volume  of  1.375,  and  saturated  air  at  the 
same  temperature  2.672,  or  about  double. 

Conceding  that  only  a  small  part  of  the  theoretical 
expansion  can  be  realized  in  practice,  as  the  air  when  ex- 
panded in  the  motor  cylinders  is  cooled  very  rapidly 
and  there  are  other  losses,  there  is  still  a  wide  margin  to 
justify  the  claim  of  double  power  from  heating  the  air. 
This  declaration  was  fully  sustained  by  actual  work  on 
the  Second  Avenue  Railroad,  where  double  runs  of  6J 
miles  had  been  accomplished  with  the  same  expenditure 
of  moist  and  heated  air  as  single  runs  of  3|  miles  with 
dry  air.  The  inevitable  conclusion  that  results  therefrom 
is  that  the  power  secured  and  utilized  in  air  compressed 
with  the  best  engines  and  compressors  now  in  use  costs, 
as  compared  with  ordinary  steam  street  motors,  only 
one-fourth  as  much  per  horse-power  measured  by  the 
coal  actually  consumed. 

The  air  is  not  admitted  to  the  motor  cylinder  at  350 
pounds  pressure,  but  at  a  much  lower  pressure,  so  that 
after  passing  the  tanks  and  becoming  heated  and  charged 
with  vapor,  it  enters  the  cylinders  at  250  pounds, 
requiring  but  a  comparatively  small  volume  of  the  dry 
air  from  the  reservoirs  to  do  the  work. 

This  uniformity  of  pressure  is  secured  by  means  of  a 
reducing  valve  placed  in  the  pipe,  which  acts  automati- 
cally until  the  pressure  is  reduced  below  the  pressure  of 
admission.  When  the  air  has  become  so  exhausted  as 
to  fall  below7  this  pressure,  the  reducing  valve  remains 
fully  open. 

If  the  water  should  be  cooled  down  100  degrees,  the 
power  of  the  heated  air  would  be  reduced,  but  would 
still  retain  great  efficiency. 


TESTS   OF    HARDIE   COMPRESSED    AIR    MOTOR.       67 

It  can,  therefore,  readily  be  understood  that  a  very 
important  gain  results  from  heating  the  air,  and  the 
economy  of  the  arrangement  is  so  great  that  it  should 
never  be  omitted.  The  use  of  a  small  petroleum  lamp 
to  retain  a  high  temperature  in  the  water  would  add  to 
the  efficiency. 

COST  OF  HEATING  THE  AIR  PER  MILE. 

To  raise  5  cubic  feet  of  water  from  212°  to  328° 
requires,  as  we  have  seen,  36,192  units,  or  1251  units 
per  mile.  Allowing  8000  nnits  of  heat  per  pound  of 
coal  consumed,  the  coal  required  to  heat  the  5  cubic  feet 
of  water  would  be  36,192  8000  =  4.5  pounds,  at  a 
cost  of  one  cent,  and  this  is  less  than  average  duty. 

It  would  seem  from  the  result  of  this  calculation  that 
fully  100  per  cent,  had  been  added  to  the  power  of  the 
engine  and  to  the  miles  run,  at  a  cost  of  one  cent  in  coal 
for  heating  the  water. 

How  MANY  MILES  WILL  THE  PNEUMATIC  MOTOR 
RUN? 

The  air  reservoirs  contain  160  cubic  feet  at  24  atmos- 
pheres. The  equivalent  at  one  atmosphere  is  3840  cubic 
feet.  Allowing  one-third  to  be  retained  as  reserve,  there 
will  be  left  to  be  utilized  2560  cubic  feet.  But  in  con- 
sequence of  vapor  and  expansion  by  heat,  this  quantity 
is  practically  equivalent  to  5120  cubic  feet  at  the  escaping 
tension.  The  number  of  cubic  feet  of  air  and  vapor 
expended  per  mile  run  has  already  been  ascertained  to 


68  STREET    RAILWAY    MOTORS. 

be  720  cubic  feet ;  and  5120  -=-  720  =  7.1  miles  nearly, 
still  leaving  a  reserve  of  one-third. 

But  it  has  been  found  that  the  actual  performance 
exceeds  this  theoretical  limit,  and  that  starting  with  350 
pounds  pressure,  9|  miles  have  been  run  with  a  reserve 
of  85  pounds.  How  can  this  be  accounted  for  ?  Simply 
by  the  fact  that  the  estimate  of  7.1  miles  was  based  on 
the  supposition  that  a  cylinder  of  mixed  air  and  vapor 
at  atmospheric  tension  was  expended  at  each  stroke.  If 
nearly  50  per  cent,  more  duty  was  actually  secured,  it 
proves  that  less  than  a  cylinder  of  air  and  vapor  did  the 
work. 

But,  it  may  be  asked,  How  is  this  possible?  How 
can  expansion  be  carried  beyond  atmospheric  tension 
without  creating  a  vacuum,  and  losing  power  by  working 
against  back  pressure  ?  This  question  was  asked  of  Mr. 
Hardie,  and  the  explanation  brought  to  light  another 
beautiful  feature  of  this  motor.  There  are  valves  called 
suction- valves  in  the  exhaust  passages,  and  whenever 
the  tension  of  air  in  the  cylinder  falls  below  that  of  the 
atmosphere,  these  valves  open  and  permit  the  stroke  to 
be  completed  without  back  pressure,  so  that  it  is  not 
necessary  to  use  more  air  than  will  overcome  the  resist- 
ances, and  this  may  vary  from  a  full  cylinder  to  a  very 
small  fraction,  or  between  limits  as  extreme  as  one  to 
thirty. 

INCREASED  POWER  FROM  MOTOR  CYLINDERS  ACTING 
AS  AIR  PUMPS. 

The  motor  cylinders  are  so  arranged  that  in  descend- 
ing steep  grades  they  act  as  air  pumps,  and  at  the  same 


TESTS   OF    HARDIE    COMPRESSED    AIR   MOTOR.       69 

time  as  brakes,  by  which  means  it  is  found,  as  stated  by 
the  company's  engineer,  Mr.  Hardie,  that  in  running 
down  grade  on  the  Second  Avenue  Railroad,  pumping 
back  against  a  pressure  of  200  pounds  in  the  receiver, 
the  pressure  was  increased  7  pounds  in  a  distance  of  0.4 
mile.  As  it  requires  360  cubic  feet  to-  run  one  mile, 
0.4  mile  would  require  144  cubic  feet. 

If  the  pressure  were  increased  7  pounds  in  a  receiver 
containing  160  cubic  feet  at  200  pounds,  the  air  pumped 
back  would  have  been  5.3  cubic  feet  at  200  pounds  in 
0.4  of  a  mile,  equal  to  69  cubic  feet  at  atmospheric  ten- 
sion, which  is  about  half  the  amount  of  air  that  would 
have  been  expended  in  running  an  equal  distance  with 
the  aid  of  the  heat  on  a  level,  with  a  consumption  of  one 
cylinder  of  air  at  each  stroke,  but  with  actual  results  50 
per  cent,  greater. 

To  appreciate  the  importance  of  this  result,  it  must 
be  observed  that  not  only  is  all  the  air  saved  in  running 
down  hill  and  not  a  particle  used,  but  half  as  much  or 
more  as  would  have  been  expended  with  the  aid  of  heat 
and  vapor  upon  a  level  is  pumped  back  again,  and  at  the 
same  time  the  action  of  pumping  back  acts  as  a  most 
efficient  brake,  the  efficacy  of  which  is  spoken  of  by  the 
intelligent  mechanical  engineer  of  the  Delamater  Works 
in  terms  of  the  highest  commendation. 

This  is  certainly  a  most  extraordinary  result,  and  so 
large  a  percentage  of  gain  is  only  possible  in  conse- 
quence of  the  great  expansion  in  the  motor  cylinders. 
The  air  and  vapor  escape  at  the  tension  of  the  atmos- 
phere, without  the  noise  which  attends  the  escape  of  high- 
pressure  steam.  When  the  air  at  atmospheric  tension 
is  pumped  back  again,  it  can  readily  be  perceived  that  a 


70  STREET    RAILWAY    MOTORS. 

certain  percentage  of  the  power  expended  will  be  re- 
stored, since  only  half  a  cylinder  of  air  or  less  is  re- 
quired to  do  the  work  at  each  stroke. 

Such  a  contrivance  can  only  be  characterized  as  admir- 
able, and,  it  will  be  perceived,  adds  another  considerable 
percentage  to  gain  in  coal  as  compared  with  steam 
motors. 

When  a  locomotive  engine  shall,  while  running,  be 
able  to  manufacture  coal  and  store  it  in  the  tender,  it 
will  then  be  able  to  rival  this  performance  of  the  pneu- 
matic motor. 

It  has  been  shown  that  at  atmospheric  tension  the 
contents  of  the  motor  cylinder  are  just  one  cubic  foot 
for  each  revolution  of  the  car  wheels  and  that  there  are 
720  revolutions  per  mile.  There  should  be  pumped 
back  therefore  720  cubic  feet  if  the  inclination  were 
steep  enough  to  employ  full  power,  which  is  found  by 
computation  to  be  198  feet  per  mile,  and  when  heated, 
saturated,  and  expanded,  this  air  should  run  the  car  two 
miles  or  more,  instead  of  one.  In  other  words,  while 
running  down  hill  one  mile,  on  a  grade  of  198  feet,  the 
motor  theoretically  might  store  up  enough  to  run  it  two 
miles  on  a  level ;  and  recent  experiments  have  shown 
that  50  per  cent,  may  be  added  to  this  estimate. 

HEAT  AND  COLD  BY  COMPRESSION  AND  EXPANSION. 

In  some  forms  of  pneumatic  apparatus  much  incon- 
venience has  been  experienced  from  the  heat  liberated  in 
compression,  and  again  from  the  intense  cold  resulting 
from  expansion,  which  deposited  ice  in  the  cylinders  and 
ports  when  moisture  was  present,  as  it  always  is  in  air 


TESTS   OF    HARDIE    COMPRESSED    AIR   MOTOR.       71 

in  its  ordinary  condition.  It  has  been  stated  by  writers 
on  pneumatics  that  one  pound  of  air  at  one  atmosphere 
and  at  60°  compressed  to  two  atmospheres  is  heated 
116°,  and  the  units  of  heat  liberated  per  pound  are 
0.238  x  116  =  27.6  units. 

Conversely  the  expansion  of  air  causes  an  absorption 
of  heat  or  production  of  cold  to  a  corresponding  extent. 

The  compressors  constructed  at  the  Delarnater  Works, 
in  New  York,  secure  comparative  exemption  from  the 
inconvenience  both  of  heat  and  cold.  The  apparatus 
now  in  actual  use  on  the  Second  Avenue  Railroad  con- 
sists of  an  engine  with  two  steam  cylinders  12  inches 
diameter  and  36  inches  stroke,  operating  two  double- 
acting  compressors  of  same  stroke,  one  of  which  has  a 
diameter  of  13  inches  and  the  other  a  diameter  of  6J 
inches. 

The  number  of  strokes  per  minute  in  charging  a  car 
are  76  at  the  commencement,  and  70  at  the  end  ;  the 
difference  being  caused  by  the  difference  in  work  to  be 
performed. 

The  fly-wheel  weighs  about  4  tons,  with  a  diameter  of 
about  10  feet. 

The  air  cylinders  are  jacketed,  and  a  current  of  cold 
water  circulates  around  them  continually. 

The  air  compressed  in  the  first  compressor  to  about 
5  atmospheres,  passes  into  a  tank  of  water  in  which  the 
water  is  kept  cool,  and  thence  into  the  second  compres- 
sor, where  it  is  reduced  in  volume  one-fifth  a  second 
time,  making  one-twenty-fifth  of  its  original  volume. 

The  water-tanks  perform  a  most  important  office,  not 
only  in  cooling  the  air,  but  in  drying  it  also. 


72  STREET   RAILWAY   MOTORS. 

The  explanation  of  this  apparent  inconsistency  is 
simple. 

Ordinary  atmospheric  air  contains  more  or  less  water, 
which  on  reduction  of  temperature  below  the  dew-point 
is  deposited  to  a  certain  extent  on  cold  surfaces. 

In  compressing  25  cubic  feet  of  air  into  one,  and 
cooling  it  with  water,  it  is  estimated  that  twenty-four 
parts  out  of  twenty-five  of  the  water  will  be  absorbed 
and  removed. 

When  this  dry  air  is  again  expanded  by  being 
utilized  in  the  motor,  it  cannot  deposit  ice,  because 
there  is  so  little  contained  water  to  form  ice,  and  hence 
the  fact,  which  it  is  said  has  excited  great  surprise 
amongst  observers,  that  no  frost  whatever  was  formed 
except  on  the  outside  of  the  pipe  from  the  condensation 
of  outside  moisture. 

Mr.  Hardie  stated  that  when  the  pressure  ran  low 
and  the  temperature  of  the  tanks  fell  below  100°  frost 
began  to  be  formed.  This  is  precisely  as  should  be  ex- 
pected. If  air,  in  being  compressed  to  one-half  its 
volume,  liberates  116  degrees  of  heat,  it  must  absorb  an 
equal  amount  in  expanding,  and  if  the  water  has  cooled 
so  low  as  not  to  furnish  sufficient  heat  to  compensate  for 
it,  the  moisture  taken  from  the  water-tank  must  form 
frost  to  some  extent. 

A  suggestion  may  here  be  oifered  in  regard  to  the 
future  possibilities  of  compressed  air.  Why  can  it  not 
be  compressed  to  high  tensions  by  cheap  power,  trans- 
mitted for  considerable  distances  through  pipes,  and  used 
expansively  in  compound  engines  with  heater,  without  the 
annoyance  and  risk  of  large  boilers  and  coal  consump- 
tion on  the  premises  w^here  the  powrer  is  utilized  ?  There 


TESTS   OF    HARDIE   COMPKESSED   AIR   MOTOR.       73 

is  no  reason  to  apprehend  danger  from  this  increase  of 
pressure.  The  air  receivers,  unlike  steam  boilers,  never 
deteriorate ;  the  air  being  perfectly  dry,  and  the  receivers 
coated  internally,  there  can  be  no  rust :  and  if  pressure  is 
increased,  the  thickness  of  material  can  be  increased  also, 
and  the  factor  of  safety  remain  the  same.  Any  defect 
of  material  or  workmanship  would  be  revealed  by  proper 
tests;  and  if  a  rupture  should  occur,  there  would  be  only 
an  escape  of  cold  air — no  steam  and  no  fragments  of 
iron.  A  cylinder,  fully  charged,  was  ruptured  in  France 
purposely  by  the  fall  of  a  heavy  weight.  The  air 
escaped  simply  with  a  hissing  sound  ;  no  fragments  were 
projected  as  in  explosions  of  steam  boilers,  and  cold,  not 
heat,  resulted  from  the  expansion.* 

WHAT  GRADES  CAN  THE  PNEUMATIC  MOTOR  OVER- 
COME, AND  WHAT  LOADS  CAN  IT  CARRY  ? 

These  are  pertinent  questions,  and  can  be  readily 
answered.  Ordinary  locomotives  are  so  proportioned  in 
their  boiler  and  cylinder  capacity  as  to  be  able  to  slip 
their  wheels  on  a  dry  rail  if  the  engine  should  be  chained 
fast,  so  that  it  could  not  advance  upon  the  track. 

In  that  case  the  adhesion,  which  is,  at  a  maximum, 
about  one-fifth  of  the  weight  upon  the  drivers,  measures 
the  power  of  the  engine,  and  not  the  pressure  in  the 
cylinders.  The  power  varies,  and  is  greatly  reduced  in 
bad  conditions  of  the  track. 

Power  of  Motor  Cylinders. — Assume  that  the  air  is 
used  under  16  atmospheres,  cut  off  at  one-sixteenth,  and 

*  This  was  written  in  1879.  At  the  present  time,  1893,  more 
than  25,000  horse-power  are  employed  in  this  way  in  Paris  alone. 


74  STREET    RAILWAY    MOTORS. 

expanded  to  fill  a  cylinder  at  atmospheric  tension,  giving 
mean  pressure  at  0.236.  The  initial  pressure  being  16 
atmospheres,  the  mean  pressure  is  16  x  0.236  =  3.776 
atmospheres,  and  3.776  x  1 5  =  56.64  pounds  per  square 
inch.  The  diameter  being  6J  inches,  the  area  is  33.18, 
and  the  piston  pressure  33.18  X  56.64  =  1879  pounds. 
If  the  air  should  be  cut  off  at  -J,  instead  of  y1^-,  the  mean 
pressure  would  be  6.158,  and  the  crank  pressure  3064. 

There  are  2  cylinders,  cranks  at  right  angles,  one  at 
full  stroke  when  the  other  is  on  its  centre.  The  weight 
of  the  car  loaded  is  8  tons.  There  are  four  wheels  con- 
nected. Weight  on  drivers  16,000,  adhesion  one-fifth 
•a  3200  pounds.  The  radius  of  the  wheel  is  14  inches, 
and  of  the  crank  6 J  inches,  then  3200  X  £.£  =  6880 
pounds  to  be  exerted  on  the  crank,  not  allowing  for  fric- 
tion of  machinery,  if  it  be  required  to  slip  the  wheels  on 
a  dry  rail.  Or,  stated  in  other  terms,  the  power  of  1879 
pounds  at  the  crank  is  »quivalent  to  871  at  the  rail,  and 
3064  at  crank  to  1422  at  rail. 

The  power  of  the  motor  cylinders  with  ordinary 
consumption  of  air  is  therefore  insufficient  to  slip  the 
wheels  on  a  dry  rail,  but  with  street  motors  so  large  an 
amount  of  cylinder  power  as  would  be  required  for  that 
purpose  is  unnecessary  ;  owing  to  the  frequent  bad  con- 
dition of  the  track,  a  large  surplus  of  adhesion  is  re- 
quired. The  cylinder  power  can  be  increased  four-fold 
by  admitting  a  full  cylinder  of  air ;  but  this  would  be 
objectionable,  as  causing  waste  of  air  and  noise  from 
exhaust,  except  in  overcoming  great  resistances  of  short 
duration,  as  in  pulling  the  motor  over  cobble-stones 
when  derailed. 

With  a  small  motor  of  6  tons  the  adhesion  would  be 


TESTS   OF   HARDIE   COMPRESSED   AIR   MOTOR.       75 

reduced  to  2400  Ibs.,  and  the  crank  pressure  required  to 
slip  the  wheels  to  5160  Ibs.  The  adhesion  in  ordinary 
conditions  of  the  rail  is  therefore,  as  it  should  be,  in 
excess  of  the  cylinder  power,  and  the  wheels  can  slip 
only  in  consequence  of  ice  and  snow.  It  remains  to  de- 
termine the  power  for  propulsion  on  a  straight  and 
level  track  and  the  power  required  on  grades. 

The  traction  of  ordinary  railroad  trains  is  9.2  pounds 
per  ton  on  a  straight  and  level  road,  based  on  the  regu- 
lar business  of  the  Pennsylvania  Railroad ;  but  with  a 
street  motor  it  is  said  to  require  about  25  pounds  per  ton, 
eight  tons  require  200  pounds,  and  this  resistance  acting 
on  a  lever  of  14  inches  from  the  axle,  while  the  propel- 
ling power  acts  with  6J  inches,  will  increase  the  power 
on  the  crank  to  200  X if =430  pounds. 

As  the  power  on  the  crank  with  the  8  ton  motor  is 
1879  Ibs.,  it  would  be  sufficient  to  move  4  such  cars, 
or  32  tons,  on  a  straight  and  level  road,  not  allowing 
for  friction  of  machinery  and  losses  in  transmission  of 
power  from  the  crank,  if,  as  has  been  stated,  the  traction 
does  not  exceed  25  pounds  per  .ton,  upon  which  this 
estimate  is  based.  It  was  found  that  when  dry  air  was 
used  and  the  machinery  was  cold,  the  pressure  of  the  air 
by  gauge  indications  being  20  Ibs.,  it  required  the  full 
head  to  propel  the  car,  while,  where  warm  air  was  used, 
the  car  moved  when  the  gauge  indicated  considerably 
less  pressure. 

Twenty  pounds  pressure  is  1J  atmospheres.  The 
average  mean  working  pressure  is  3.776  atmospheres. 
Twenty  pounds  produces  625  Ibs.  crank  pressure,  or 
300  at  rail,  and  if  this  amount  was  required  to  overcome 
friction  and  move  the  motor,  it  would  be  equivalent  to 


76  STKEET    RAILWAY    MOTORS. 

37J  pounds  per  ton,  instead  of  25  pounds,  and  absorb 
50  per  cent,  more  power  than  has  been  allowed ;  but  it  is 
stated  that  there  was  a  back  pressure  at  the  time  of 
several  pounds  per  square  inch,  in  consequence  of  the 
small  size  of  the  exhaust  ports,  which  would  cover  a 
considerable  part  of  this  difference.  It  is  possible, 
therefore,  that,  with  the  air  heated,  the  traction  may  not 
exceed  25  pounds  per  ton  ;  but  it  would  be  well  to  test 
both  the  traction  of  the  motors  and  of  ordinary  cars  by 
a  dynamometer. 

GRADES. 

It  has  been  shown  that  if  air  is  admitted  into  the 
working  cylinder  at  a  pressure  of  16  atmospheres,  cut 
off  at  one-sixteenth  of  the  stroke  and  expanded  to 
atmospheric  tension,  the  mean  pressure  on  the  crank 
would  be  1879  pounds  and  the  equivalent  to  overcome 
resistance  at  the  rail  871  pounds,  capable  of  moving  on 
a  straight  and  level  road,  if  all  could  be  utilized,  4  cars 
of  8  tons  with  traction  of  25  pounds  per  ton,  and 
certainly  2  cars. 

Also  if  the  air  should  be  cut  off  at  ^,  the  mean  crank 
pressure  would  be  3064  pounds  and  the  equivalent  at 
the  rail  1422  pounds,  capable  of  moving  4  such  cars 
upon  a  level.  As  the  angle  of  friction  with  traction  of 
25  Ibs.  per  ton  is  66  feet  to  the  mile,  the  eight  ton 
motor  should  be  able  to  haul  twice  its  own  weight  on  a . 
grade  of  66  feet  or  2  cars,  on  a  grade  of  132  feet  1  car ; 
but  2  cars  could  be  hauled  by  increasing  the  amount  of 
air  and  cutting  off  say  one-sixth,  instead  of  one-eighth. 

The    eight   ton  motor   without   extra   cars   attached 


TESTS   OF    HARD  IE   COMPRESSED    AIR   MOTOR.        77 

should  be  able  to  overcome  the  steepest  grades  usually 
found  on  horse  railroads.  The  steepest  grade  on  the 
Second  Avenue  Kailroad  is  said  to  be  230  feet  to  the 
mile,  or  one  in  twenty-three.  The  power  with  a  full 
cylinder  of  air  would  be  about  8  times  the  average 
power  expended  in  working,  and  consequently  the 
reserve  is  large  enough  to  overcome  great  resistances  of 
limited  duration. 

SMALL  MOTORS  or  5  TONS  WITH  CARS  ATTACHED. 

It  would  be  a  most  serious  disadvantage  if  the  gen- 
eral introduction  of  pneumatic  motors  should  require 
the  abandonment  of  the  old  plant.  Fortunately  such 
abandonment  is  not  only  unnecessary,  but  the  best 
possible  system  for  the  economical  operation  of  a  line 
and  for  the  accommodation  of  the  public  consists  in  the 
use  of  small  motors,  or  of  combination  car  and  motor 
capable  of  carrying  from  one  to  three  additional  cars  in 
a  train  under  one  conductor,  at  hours  when  the  travel 
requires  it. 

Suburban  residents  desire  frequently  k)  make  social 
visits  or  to  attend  lectures  or  places  of  amusement  in  the 
neighboring  cities,  and  can  testify  to  the  discomfort,  not 
to  say  danger,  of  riding  home  late  at  night  with  one 
foot  on  the  platform  and  the  other  in  space. 

The  ordinary  horse  car,  loaded,  weighs  about  five 
tons,  the  motor  would  weigh  about  the  same,  or  with 
six  tons  would  admit  a  large  increase  of  reservoir 
capacity  ;  there  would  then  be  no  pretext  for  objection 
on  the  ground  of  injury  to  track.  It  could  run  with 


78  STREET   RAILWAY    MOTORS. 

one  car  in  the  middle  of  the  day,  and  morning  and 
evening  with  2  or  3  under  one  conductor.  It  could 
make  the  trip  in  half  the  time,  certainly  in  two-thirds, 
of  the  horse-car  and  take  the  place  of  horses,  the  sale  of 
which  would  nearly  or  quite  pay  for  the  motor,  so  that 
there  would  be  but  little,  if  any,  increase  of  capital  for 
street  motors,  and  nothing  except  for  engines  and  com- 
pressors at  the  station. 

The  small  motors,  weighing  6  tons,  would  have  the 
same  cylinder  power  as  the  8-ton  motors  previously  de- 
scribed, which  gives  871  or  1422  pounds  at  the  rail,  as 
the  air  is  cut  off  at  ^g-  or  J  of  the  stroke.  The  adhesion 
with  dry  rail  is  2500  Ibs.,  and  the  traction  of  the  motor 
at  25  Ibs.  per  ton  (3  x  25  =  150  Ibs. 

If  these  small  motors  should  be  used  to  haul  ordinary 
horse-cars,  it  becomes  necessary,  in  estimating  the  per- 
formance of  the  motor,  to  know  the  traction  of  such 
cars.  For  obvious  reasons  this  traction  must  be  less 
per  ton  than  that  of  the  motor,  and  yet  more  than  that 
of  ordinary  railroad  cars,  which  is  9  pounds  per  ton. 
Probably  15  pounds  per  ton  would  be  a  full  allowance 
for  the  traction  of  ordinary  horse  railroad  cars,  and  a 
train  of  one  6- ton  motor  and  two  ordinary  cars  of  5 
tons  each,  loaded,  would  make  the  weight  of  the  train 
16  tons,  and  the  traction  300  pounds — an  average  for 
the  train  of  18.8  pounds  per  ton.  And  18.8  pounds  per 
ton  traction  would  give  the  angle  of  friction  at  which 
the  train  would  descend  by  gravity  =  44J  feet  to  the 
mile. 

The  train  of  one  small  motor  and  two  cars  could 
ascend  grades  of  178  feet  to  the  mile,  and  with  one  car 


TESTS   OF    HARDIE   COMPRESSED    AIR   MOTOR.        79 

grades  of  240  feet  to  the  mile,  and  steeper  grades  could 
be  overcome  by  using  more  air,* 

The  separate  motor,  not  intended  to  carry  passengers, 
except,  perhaps,  on  top,  would  permit  an  increase  of 
reservoir  capacity  from  160  to  225  cubic  feet;  and  if 
reservoirs  be  placed  also  under  the  seats  of  each  car,  the^_ 
capacity  of  a  two-car  train  with  motor  would  be  ex-,  ' 
tended  to  325  cubic  feet,  or  doubled,  and  the  run  to  ^.2  ; 
miles.  If,  in  addition,  in  speculating  upon  the  possi^ 
bilities  of  the  future,  the  reservoir  pressure  should  bcN 
increased  to  500  pounds,  instead  of  350,  the  run  would 
be  extended  43  per  cent.,  or  to  17  miles,  and  with  one 
car  attached  to  motor  instead  of  two,  still  further.  For 
working  elevated  railroads,  as  a  substitute  for  steam, 
the  pneumatic  motor  is  the  perfection  of  a  propelling 
power.  The  motor  itself  could  be  filled  with  air  reser- 
voirs, giving,  with  the  addition  of  reservoirs  under  the 
seats  of  the  cars,  almost  unlimited  capacity,  and  there  is 
no  run  within  suburban  limits  that  would  be  beyond 
the  power  of  the  motor,  with  a  single  station  in  the 
middle  of  the  road  to  reinforce  the  pressure.  The  cost 
of  fuel  would  be  reduced  fully  66  per  cent.,  and  noise, 
dust,  steam,  and  sparks  from  motor  avoided. 

If  a  motor  should  run  off  the  track,  it  has  power  to 
run  itself  on  the  street  pavements,  and  can  be  readily 
replaced  by  the  aid  of  crowbars.  If  the  machinery 
should  become  deranged,  another  motor  could  push  it, 

*  Since  the  above  was  written  further  experiments  have  shown 
that  the  increased  consumption  of  air  by  attaching  horse-cars  to 
the  motor  is  about  the  amount  that  could  be  supplied  by  reser- 
voirs under  the  seats,  and,  consequently,  that  the  distance  run 
need  not  be  diminished  by  attaching  additional  cars  if  so  provided. 


80  STREET   RAILWAY   MOTORS. 

and  by  a  simple  hose  attachment  the  air  in  the  disabled 
engine  could  work  the  machinery  of  the  helper. 

HORSE-POWER  OF  THE  HARDIE  MOTOR. 

With  cylinders  on  motor  6J  inches  diameter  and  13 
inches  stroke,  pressure  of  air  16  atmospheres,  cut  off  at 
one  sixteenth  of  stroke,  giving  average  pressure  56.64  Ibs. 
per  square  inch,  and  speed  of  motor  six  miles  per  hour, 
the  horse-power  applied  to  pistons  will  be  found  to  be 
17.7,  or,  if  the  speed  is  four  miles  per  hour,  11.8  horse- 
power. 

Area  of  piston  33.18  square  inches.  Travel  of  each 
piston  22  inches  to  each  revolution.  720  revolutions 
per  mile  =3120  feet  for  both  pistons  per  mile.  * 

3120  x  33.18  x  56.64=  5,862,480  foot-pounds  per 
mile  =  586,248  foot-pounds  per  minute,  and  586,248 
-*-  33,000  =  17.7  horse-power. 

This  assumes  that  the  air  operates  upon  the  piston  to 
the  full  limit  of  the  stroke,  but  with  less  resistance  much 
less  air  is  used,  and  the  horse-power  will  be  reduced  ;  on 
the  other  hand,  there  may  be  occasions  when  a  temporary 
increase  becomes  necessary.  By  letting  in  a  full  pres- 
sure of  air  more  than  three  times  the  normal  pressure 
can  be  applied  immediately. 

A  few  minor  points  in  favor  of  the  motor  will  be 
stated.  Skilled  engineers  are  not  required  to  run  them  ; 
a  man  of  ordinary  intelligence  can  learn  to  run  these 
motors  in  a  single  trip.  What  is  a  most  remarkable  and 
beautiful  feature  of  the  contrivance  is  that  a  driver, 
however  ignorant  or  careless  he  may  be,  cannot  fail  to 
use  exactly  the  proper  amount  of  air  for  the  resistance 


TESTS    OF    HARDTE    COMPRESSED    AIR    MOTOR.        81 

to  be  overcome,  and  cannot  waste  it.  If  he  admits  too 
little,  the  car  slackens  speed  or  stops ;  if  too  much,  he 
must  apply  the  brake.  All  is  done  by  the  movement 
of  a  lever,  back  or  forward  ;  no  other  brake  is  needed, 
and  the  motion  of  the  car  is  a  perfect  governor. 

Another  advantage  of  the  motors  is  that  the  view  of 
the  track  is  unobstructed  and  can  be  seen  from  the  plat- 
form on  which  the  driver  sits,  while  horses  obstruct  the 
view  of  the  track  for  30  feet. 

On  a  level  track  the  car  can  be  stopped  within  its 
length  when  running  at  a  speed  of  12  miles  per  hour, 
and  on  grades  in  a  time  longer  or  shorter  in  proportion. 
The  brake  can  never  be  out  of  order  so  long  as  the  car 
has  the  ability  to  move  at  all.  The  brake  consists  in  a 
full  or  partial  reversion  by  moving  a  lever. 

If  the  lever  should  get  out  of  order,  which  is  scarcely 
within  the  bounds  of  possibility,  the  car  could  not  move 
at  all,  therefore  the  brake  cannot  fail.  It  was  noticed 
also  in  running  along  the  Second  Avenue  Railroad  on 
the  motor  that  horses  on  the  opposite  track  meeting  the 
motor  would  sometimes  shy,  but  other  horses  not  on  the 
track  did  not  notice  it.  The  car  horses  would,  no  doubt, 
soon  become  accustomed  to  the  motor,  but  as  its  general 
use  would  supersede  horses  altogether,  this  fact  is  of 
little  consequence. 

OBJECTIONS. 

A  criticism  of  the  motor  has  been  made  by  a  mechan- 
ical engineer  of  some  prominence,  which  can  only  be 
accounted  for  on  the  supposition  that  the  letter  which 
recites  the  objections  was  written  without  consideration. 
6 


82  STREET    RAILWAY    MOTORS. 

It  is  desirable,  however,  to  have  objections  stated ; 
when  they  can  be  shown  to  be  groundless  they  serve  to 
inspire  and  increase  confidence. 

The  objections  were : 

1.  The  air  car  requires  50  horse-power  in  compressors 
to  keep  it  in  operation. 

True !  But  if  dry  air  be  used  the  same  engine  will 
charge  7  cars  per  hour,  and  if  moist  and  heated  air  be 
used  14  cars,  if  the  run  should  not  be  increased  and  only 
half  the  air  should  be  required,  which  is  only  4  horse- 
power to  a  car,  and  each  horse-power  costs  in  coal  con- 
sumed one-fourth  to  one-third  as  much  as  in  a  street 
motor. 

Second  objection.  The  cost  of  repairs  for  the  steam 
cars  would  be  less  than  for  the  air  car. 

Arts.  No  reasons  are  given,  and  the  fallacy  of  the 
assertion  is  self-evident.  There  is  no  fire-box  to  burn 
out,  and  no  boiler  to  rust,  burn  out,  or  explode.  The 
reservoirs,  filled  with  air  absolutely  dry,  are  as  nearly  im- 
perishable as  anything  on  this  mundane  sphere  can  be. 
The  parts  liable  to  wear  by  friction  are  the  same  as  on 
other  engines,  neither  more  nor  less  expensive  to  repair, 
but  the  heaviest  expenses  of  fire-box,  boilers,  and  flues 
are  all  saved. 

Third  objection.  The  air  car  is  not  so  reliable  as  a 
steam  car,  as  it  has  not  the  same  surplus  for  emergencies. 

Ans.  Why  not  ?  A  surplus  is  provided  of  33  per 
cent.  Does  a  locomotive  finish  its  trip  with  as  much 
reserve  power  in  coal  and  water  in  its  tender  ?  Besides, 
all  the  cars  of  a  train  can  have  air  cylinders  under  the 
seats,  the  whole  of  which  can  be  held  in  reserve. 

The  above  are  the  only  objections  advanced. 


TESTS  OF  HARDIE  COMPRESSED  AIR  MOTOR.     83 

LOCATION  OF  POWER  PLANT. 

. 
Considerations  of  economy  would  lead  to  the  location 

of  the  power  plant  at  or  near  the  middle  of  the  section 
of  the  road  to  be  operated,  for  the  reason  that  the  power 
could  be  readily  renewed  by  a  simple  hose  attachment 
while  passing  the  central  station,  whereas  if  located  at 
one  end  a  supply  for  a  run  of  double  the  length  would 
be  required ;  but  it  may  be,  and  in  a  majority  of  cases 
probably  will  be,  found  most  economical  to  locate  the 
compressed  plant  back  of  the  main  thoroughfare, 
where  land  is  of  comparatively  little  value,  and  trans- 
mit the  compressed  air  through  pipes  to  any  number 
of  reservoirs  conveniently  located  along  the  route. 

These  reservoirs  would  occupy  but  little  space,  and 
would  not  require  a  front  location  upon  the  thorough- 
fare traversed  by  the  cars.  They  could  be  placed  one 
hundred  feet  or  more  in  the  rear,  or  even  under  ground, 
and  from  them  strong  wrought-iron  pipes  could  lead  to 
the  track,  where  an  air  plug  with  hose  attachments  covered 
by  a  manhole  plate  would  afford  facilities  for  replenishing 
the  air  charge  of  the  motors  at  any  intervals  however 
short  that  might  be  considered  desirable.  Underground 
pipes  could  be  carried  to  the  car  sheds  to  supply  motors 
with  full  charges  while  standing  on  the  tracks. 

As  all  the  reservoirs  upon  the  line  would  be  connected 
with  each  other,  and  with  the  central  plant  the  pressure 
would  have  a  constant  tendency  to  equalize  itself 
throughout  the  whole  system,  and  a  large  reservoir  ca- 
pacity thus  created  would  be  of  great  advantage  in  insur- 
ing an  ample  supply  of  air  under  nearly  uniform  pressure. 

Oil  is  frequently  transmitted  in  pipe  lines  under  a 


84  STREET   RAILWAY    MOTORS. 

pressure  of  1500  pounds  per  square  inch,  so  that  a  pres- 
sure of  even  600  pounds  would  not  require  pipes  of  ex- 
traordinary thickness. 

In  the  transmission  of  elastic  fluids  through  pipes  for 
long  distances  there  is  a  loss  of  power  due  to  friction 
dependent  upon  the  length  and  diameter  of  the  pipe,  but 
more  upon  the  velocity  of  transmission.  This  subject 
was  very  fully  investigated  by  the  writer  in  1879  in 
connection  with  the  Holly  system  for  the  transmission 
of  steam  for  heat  and  power. 

If,  for  the  present,  it  be  assumed  that  air  is  compressed 
to  40  atmospheres  at  a  central  point,  and  transmitted  by 
pipes  of  six  inches  diameter  for  utilization  in  distant 
reservoirs  and  in  quantity  sufficient  to  charge  one  car 
cylinder  of  160  cubic  feet  capacity  per  minute,  the  initial 
velocity  of  the  air  in  the  pipe  would  be  twelve  feet  per 
second  as  a  maximum,  and  the  loss  of  head  by  friction, 
based  on  the  tables  deduced  from  experiments  at  the  Mt. 
Cenis  Tunnel,  would  be  but  1.83  pounds  in  a  distance 
of  one  mile,  assuming  that  the  car  cylinders  should  be 
returned  entirely  empty  and  require  160  cubic  feet  as 
the  initial  pressure. 

But  in  the  trips  on  the  Second  Avenue  Railroad  the 
cars  returned  to  the  station  with  one-third  of  their  charge 
remaining,  or  with  8  atmospheres,  after  expending  16 
atmospheres  in  the  run ;  consequently  a  charge  of  40 
atmospheres  would  have  permitted  just  double  the  dis- 
tance to  have  been  operated  with  a  single  charge,  which 
would  be  18  miles. 

One  car  per  minute  could  be  required  on  any  city 
line  only  at  the  hours  of  maximum  business,  and  even  at 
such  hours,  if  the  cars  returned  with  partial  charges,  the 


TESTS    OF    HARDIE    COMPRESSED    AIR    MOTOR.        85 

quantity  of  air  required  for  re-charging  would  be  less  than 
the  maximum,  the  velocity  of  transmission  would  be  re- 
duced, and  the  loss  by  friction,  which  is  as  the  square  of 
the  velocity,  would  be  reduced  also.  Instead  of  dis- 
patching one  car  per  minute,  the  same  capacity  can  be 
more  economically  aiforded  by  one  motor  car  in  2  min- 
utes with  one  trailer,  and  still  more  with  2  or  3. 

It  would  seem  to  be  practicable,  therefore,  on  extended 
lines  to  locate  compressor  plants  at  intervals  of  20  or 
25  miles,  and  transmit  power  in  pipes  to  intermediate 
stations  10  or  12  miles  distant,  with  additional  interme- 
diate reservoirs  at  stated  intervals  to  be  used  in  case  of 
accident,  such  reservoirs  consisting  simply  of  a  number 
of  small  cylinders  of  steel  two  feet,  more  or  less,  in  diame- 
ter, connected  with  each  other  by  pipes.  The  cylinders 
of  small  diameter  would  be  necessary  to  secure  strength. 

Whether  the  pneumatic  system  could  be  extended  to 
supersede  steam  motors  on  ordinary  railroads  is  a  ques- 
tion that  can  be  reserved  for  future  consideration.  It 
may  be  observed,  however,  that  the  traction  on  straight 
and  level  steam  railroads  is  only  9  pounds  per  ton  for 
the  train,  while  on  ordinary  street  railroads  it  has  been 
estimated  for  the  motor  at  25  pounds.  Also,  that  in 
passenger  cars  reservoirs  of  air  cylinders  can  be  placed 
below  the  seats,  and  the  floor  of  the  car  may  rest  upon 
two  longitudinal  cylinders  supporting  in  the  middle  of 
the  car  a  number  of  transverse  cylinders.  The  frame 
could  be  of  hollow  pipes,  and  thus  a  very  considerable 
reservoir  capacity  could  be  provided  in  each  car.  A 
tender  filled  with  air  reservoirs  could  take  the  place  of 
the  ordinary  tender  with  coal  and  water.  How  far  such 
a  train  could  be  made  to  run  with  ordinary  cars  without 


86  STREET    RAILWAY    MOTORS. 

reinforcement  of  power,  and  what  the  cost  of  power  as 
compared  with  steam,  would  be  interesting  inquiries,  for 
the  determination  of  which  all  the  necessary  data  have 
not  yet  been  fully  presented,  and  it  is  moreover  foreign 
to  the  present  inquiry.  There  can  be  no  doubt,  how- 
ever, and  conclusive  evidence  can  be  and  has  been  pre- 
sented, that  for  street,  elevated,  and  underground  rail- 
roads steam  cannot  favorably  compare  with  air,  either  in 
economy,  convenience,  or  freedom  from  dirt,  smoke, 
noise,  and  other  nuisances.  In  fact,  it  can  justly  be 
claimed  that  it  fulfils  every  condition  that  could  possibly 
be  desired,  and  is  free  from  any  objection  that  can  be  urged. 

RECORD  OF  DIRECT  EXPERIMENTS  WITH  THE 
HARDIE  MOTOR. 

For  several  days  previous  to  March  12,  1879,' experi- 
ments were  made  with  the  motor  on  the  Second  Avenue 
Eailroad,  the  results  of  which  it  is  proper  to  note. 

March  9th,  started  from  depot  at  127th  Street,  and 
made  three  round  trips,  with  the  following  record  : — 

1st  trip  started  with  pressure      .         .         .     360  pounds. 
Consumed 95       " 

Returned  with 265       " 

2d  trip  started  with 265       " 

Consumed    .         .         .         .         .  95       " 

Returned  with  .         .         .         .     170       " 

3d  trip  started  with 170       " 

Consumed    .         .         .         .         .  75       " 

Returned  with 95       " 

This  result  was  so  remarkable,  that  the  President  of 
the  Company,  Mr.  F.  Henriques,  requested  the  writer  to 
superintend  some  further  experiments,  to  ascertain  if 


TESTS   OF    HARDIE   COMPRESSED   AIR    MOTOR.       87 

increased  duty  would  be  secured  by  running  at  reduced 
pressures.  Accordingly,  on  March  10th,  three  more 
trips  were  made,  with  the  following  record  : — 

1st  trip  started  with 360  pounds. 

Temperature  of  water  ....  324° 

Mean  working  pressure  while  running  .  120  pounds. 
Water  absorbed   .         .         .          .  31       " 

Pressure  on  return        ....  290       " 

Consumed 70       " 

2d  trip  started  with 286  pounds. 

Mean  working  pressure         .         .         .  120       " 
Consumed  water            .          .         .         .  •    11.3    u 

Temperature  of  water  on  return   .         .  198° 

Pressure  at  end  of  trip         .         .         .  195  pounds. 

Consumed 91       " 

3d  trip  started  with 195  pounds. 

Mean  working  pressure  until  pressure 

fell  below  .         .         .         .         .  120       " 

Water  absorbed 19.8    " 

Temperature  on  return          .         .         .  180° 
Pressure  at  end  of  trip          ...       95  pounds. 

Consumed 100       " 

The  comparison  of  these  two  tests  exhibits  very  remark- 
able results. 

The  total  consumption  of  air  in  the  three  round  trips, 
starting  with  360  pounds  and  finishing  with  95,  was 
265  pounds,  or  an  average  of  88.33  each  trip.  The 
last  trip  of  the  first  series  was  run  with  75  pounds. 
This  fact  it  is  difficult  to  explain,  as  the  water  was  cer- 
tainly much  cooler  than  at  the  start,  and  it  could  not 
have  contributed  so  large  a  proportion  of  vapor. 

In  the  first  run  of  the  second  series  the  air  consumed 
was  70  pounds  pressure,  equivalent  to  747  cubic  feet, 
or  57J  pounds  at  atmospheric  tension,  and  this  air  ab- 
sorbed the  very  extraordinary  amount  of  31  pounds  of 


88  STREET    RAILWAY    MOTORS. 

water,  or  more  than  half  a  pound  of  water  for  each 
pound  of  air,  which  is  double  the  average  consumption 
and  four  times  the  capacity  of  ordinary  air  for  moisture. 

It  will  be  observed,  also,  that  a  great  reduction  of 
temperature  from  324°  to  190°  or  126°  was  found  in 
the  two  runs. 

The  large  quantity  of  vapor  and  heat  abstracted  from 
the  water  in  the  first  run  will  fully  and  satisfactorily  ac- 
count for  the  small  quantity  of  air  consumed,  and  would 
serve  to  indicate  the  possibility  of  increasing  the  distance 
run  by  burning  gas  or  petroleum  to  replace  the  heat 
which  the  air  absorbs. 

In  the  last  run  of  the  second  series  100  pounds  were  con- 
sumed. This  was  to  have  been  expected,  as  the  water 
at  the  end  of  the  run  was  32°  below  the  boiling-point, 
and  water  instead  of  steam  was  probably  carried  out. 

On  Tuesday,  March  llth,  further  experiments  were 
made  to  determine  the  effect  of  attaching  additional  cars 
to  the  motor.  The  following  is  the  record  taken  by 
Mr.  Harley  : — 

1st  trip  started  from  127th  street,  with         .  300  pounds. 
At  depot,  97th  Street,  air  pressure        .  250       " 
Consumed  in  half  trip           .         .  50       " 
Coupled  on  2  ordinary  street  cars,  pres- 
sure at  end  of  trip,  127th  Street       .  170       " 
Consumed  with  the  2  cars  and  motor    .  80       " 
Temperature  of  water  ....  205° 

2d  trip,  started  with    .....  335  pounds. 

Run  at  mean  pressure  ....  150       " 

Cars  in  tow  ......  2 

Pressure  at  97th  Street         .         .         .  275  pounds. 

Consumed 60       " 

Water  used 14.2  " 

Reduced  pressure  in  heater  to       .         .  130       " 


TESTS   OF    HARDIE   COMPRESSED    AIR    MOTOR.        89 

2d  trip  return,  2  cars  in  tow,  started  from 

97th  Street,  pressure         .         .         .  275  pounds. 

Pressure  at  127th  Street        .         .         .  190  " 

Consumed  pressure       .         .         .         .       85  " 

Water  used 14.2  " 

3d  trip,  heated  water  again,  2  cars,  started 

from  127th  Street  with  a  pressure  of  330  pounds. 

At  97th  Street,  pressure       .         .         .  265  " 

Consumed 65  " 

Water  used 16  " 

Return,   no   cars    in  tow,  started  from 

97th  Street 250  " 

At  127th  Street 200  " 

Consumed 50  " 

Water  used 11  " 

OBSERVATIONS. 

It  appears  that  the  two  up  trips  consumed  80  and  85 
pounds  of  pressure,  and  the  two  down  trips  60  and  65 
pounds,  and  the  up  trips  required  33  per  cent,  more  than 
the  down  trips.  This  may  be  due  to  the  very  bad  condi- 
tion of  the  up  track.  The  average  round  trip  required  145 
pounds  with  two  cars  attached  to  motor,  as  against  90 
pounds  with  motor  alone,  an  increase  of  60  per  cent.,  or 
30  per  cent,  for  each  car  hauled.  The  two  cars  probably 
weighed  as  much  as  the  motor,  and,  if  so,  the  traction  of 
the  cars  would  be  15  pounds  per  ton,  assuming  the 
motor  at  25. 

The  data  furnished  by  observations  on  the  motor  will 
serve  to  indicate  the  loss  of  power  and  of  work  in  trans- 
mission from  the  piston  to  the  rail.  Starting  at  350 
pounds  pressure,  the  run  of  9f  miles  was  made  with  270 
pounds  pressure,  or  90  pounds  per  average  run,  or  298 
cubic  feet  of  air,  at  atmospheric  density,  per  mile.  As- 


90  STREET   RAILWAY    MOTORS. 

suming  for  the  present  that  the  effect  of  heating  and 
moistening  the  air  is  chiefly  to  compensate  for  the 
reduced  temperature  in  expanding,  and  to  secure  the  full 
benefit  of  isothermal  expansion,  the  foot-pounds  of  work 
per  mile  will  be  computed  on  this  basis. 

The  volume  required  per  mile  to  fill  the  capacity  of 
the  working  cylinders  is  720  cubic  feet ;  the  298  cubic 
feet  therefore  filling  40  per  cent,  of  the  cylinder  capacity, 
leaving  60  per  cent,  to  be  replaced  by  air  from  the  ex- 
haust passages,  by  the  opening  of  the  suction  valves. 

If  used  under  an  average  pressure  of  170  pounds  = 
11.33  atmospheres  indicated,  or  12.33  atmospheres 
actual,  the  atmospheric  pressure  would  be  reached  in 
13  x  0.4  =  5.2  inches  of  stroke  in  cylinders,  and  the 
mean  piston  pressure  during  the  5.2-inch  stroke  would 
be  1732  pounds. 

As  there  are  4  cylinder  discharges  to  each  revolution, 
and  720  revolutions  to  a  mile,  the  travel  of  piston  per 
mile  run  under  pressure  will  be  720  x  4  X  5.2  =14,976 
inches  =  1250  feet,  and  1250  x  1732  «  2,165,000  foot- 
pounds of  work  done  at  piston  per  mile  of  actual  run. 
If  now  it  requires  a  tractive  force  of  25  pounds  per  ton 
on  a  level  road  to  move  the  motor,  and  the  weight  be  8 
tons,  then  8  X  25  X  5280  «=»  1,056,000  foot-pounds  per 
mile,  which,  if  the  road  was  level,  would  represent  the 
actual  work  utilized  from  an  expenditure  of  2,165,000 
foot-pounds  upon  the  piston,  which  is  50  per  cent, 
nearly. 

It  would  appear,  therefore,  that  only  half  the  power 
applied  to  the  piston  is  actually  utilized  in  propulsion 
on  the  track,  and  the  balance  must  be  expended  in 
overcoming  friction  of  motor  and  other  resistances  and 


TESTS    OF    HARDIE    COMPRESSED    AIR    MOTOR.        91 

losses.  The  power  required  to  move  the  motor,  if  ap- 
plied externally,  and  also  the  traction  of  the  ordinary 
horse-cars,  is  not  known,  and  should  be  determined. 

The  computation  of  average  run  has  been  based  on 
an  expansion  of  12,  and  reaching  atmospheric  tension  at 
0.4  of  the  length  of  the  cylinder,  using  only  one-thirtieth 
part  of  a  cylinder  of  air  at  each  stroke.  If  a  full 
cylinder  of  air  should  be  used,  the  power  on  the  piston 
would  be  increased  nearly  nine  times,  but  the  consump- 
tion of  air  thirty  times. 

This  great  reserve  of  power  over  the  average  for 
ordinary  work  is  an  advantage  of  no  small  importance. 
The  reserve  of  power  can  be  drawn  upon  to  overcome 
great  resistances,  if  of  short  duration. 

As  an  illustration  of  this  fact,  and  since  the  above  para- 
graph was  written,  Mr.  James,  who  was  associate  engineer 
with  Mr.  Hardie,  states  that  on  one  occasion  the  motor 
got  off  the  track  at  a  sharp  curve  and  switch  at  the  127th 
Street  depot ;  a  ditch  had  been  dug  for  gas  pipes  and 
filled  in,  but  not  paved.  The  hind  wheels  sunk  in  the 
ditch  until  the  frame  of  the  motor  rested  on  the  pave- 
ment. A  high  pressure  was  let  on  and  the  machine 
pulled  itself  out  without  further  assistance. 

This  power  of  overcoming  great  resistances  of  short 
duration  is  of  great  value. 

In  the  consideration  of  the  question  of  hot  water 
motors,  the  position  was  taken  that  in  the  conversion  of 
hot  water  into  vapor  or  steam  nearly  a  thousand  degrees 
became  latent,  and  this  latent  heat  so  rapidly  cooled  the 
remaining  water  from  which  it  was  abstracted  that  it 
was  not  possible,  without  the  use  of  a  fire,  to  restore  the 


92  STREET    RAILWAY    MOTORS. 

heat,  and  that  the  motor  could  not  possibly  run  the  dis- 
tance claimed  for  it. 

The  observations  just  reported  on  the  Hardie  motor 
fully  sustain  these  conclusions. 

The  first  trip  in  the  second  series  started  with  full 
tank,  5  cubic  feet  or  310  pounds  of  water,  at  a  tempera- 
ture of  324°,  and  used  31  Ibs.  water. 

The  second  run  used  11.3  Ibs.,  and  the  third  19.8  Ibs., 
in  all  62.1  Ibs.,  and  the  temperature  in  return  was  180° 
with  248  pounds  of  water. 

The  differences  there  were  : — 

310  pounds  water  at  324°  =  100,440  units. 
248       "  "          180°  =    44,640      " 

Units  lost  with  62  Ibs.         5.5,800 

But  62  Ibs.  water  with  a  difference  of  temperature  of 
144°  would  remove  only  8928  units,  leaving  46,972 
units  to  be  accounted  for  as  latent  heat.  This  is  equiva- 
lent to  758  units  per  pound  of  water  evaporated. 

As  this  is  less  than  the  amount  of  latent  heat  required 
for  the  conversion  of  water  into  steam,  it  follows  that 
after  the  temperature  of  the  water  fell  below  212°,  water 
and  not  steam  must  have  been  carried  over  with  the 
air. 

If  figures  are  made  upon  the  first  two  runs  where  the 
temperature  was  maintained  above  or  near  the  boiling- 
point,  the  data  are  :  Temperature  at  starting,  324°  ;  on 
return,  198°  ;  loss,  126°.  Water  evaporated,  42.3  Ibs. 
Units  at  126°  =  5330. 

Weight  of  water  at  starting,  310  pounds ;  on  return, 
267.7  pounds. 


TESTS    OF    HARDIE   COMPRESSED    AIR   MOTOR.        93 

Thermal  units  at  start,      310  x  324=100,440 
Thermal  units  on  return,  267.7  X  198=   53,004 


Loss  of  thermal  units      .          .        47,436 
Accounted  for  by  sensible  heat-units 

as  above 5,330 


Leaves  unaccounted  for  .         .         42,106 

If  1000  units  per  pound  be  allowed  latent  for  water, 
42,300,  the  difference  is  therefore  fully  accounted  for, 
and  proves  that  where  air  is  passed  through  hot  water 
the  water  removed  carries  off  not  only  the  units  of  sen- 
sible heat  due  to  the  difference  in  temperature,  but  also 
cools  the  remaining  water  to  the  extent  of  1000°  for 
every  pound  of  water  removed. 

Another  important  observation  may  here  be  made. 
In  the  3  round  trips  of  9|  miles  the  loss  of  heat-units 
in  the  tank  was  55,800.  If  the  heat  had  been  maintained 
at  324°  by  means  of  a  small  naphtha  or  petroleum  stove 
yielding  more  than  20,000  units  in  combustion,  it  is 
reasonable  to  assume  that  15,000  units  could  be  utilized, 
and  consequently  4  pounds,  costing  not  more  than  3 
cents,  would  supply  the  units  for  more  efficient  reheating 
at  a  cost  of  3  mills  per  mile  run  of  motor.  This  re- 
heating, it  will  be  remembered,  doubles  the  run  with  a 
given  volume  of  air;  in  other  words,  5  miles  would  be 
added  to  the  run  of  the  motor  at  a  cost  of  3  cents,  which 
is  a  maximum  cost. 

Small  as  this  is,  it  is  still  higher  than  Mr.  Hardie's 
estimate  for  hot  water  drawn  from  stationary  tanks.  He 
allows  J  of  the  coal  used  in  compression.  In  this  case 
6  pounds  of  coal  should  furnish  the  55,800  units,  at  a  cost 


94  STREET    RAILWAY   MOTORS. 

of  one  cent ;  but  by  referring  to  the  record,  it  appears 
that  where  the  temperature  of  the  water  was  324°  at  the 
start,  the  run  was  made  with  70  pounds  pressure,  and 
could  probably  have  been  made  at  65  pounds  if  the  tem- 
perature during  the  run  had  been  maintained  at  324°. 
At  this  rate  the  air  evaporated  per  mile  would  have  been 
reduced  from  300  cubic  feet  to  240. 

Another  observation  on  this  very  important  subject 
of  reheating  should  be  made.  The  air  was  not  only 
expanded  by  the  heat,  so  as  to  exert  a  higher  pressure 
from  that  cause,  but  there  were  carried  over  62.1  pounds 
of  water  in  the  form  of  steam,  which  would  be  equiva- 
lent to  1700  cubic  feet  of  air  at  atmospheric  tension,  with 
the  additional  advantage  of  a  warm  exhaust  and  no 
possibility  of  frost.  This  accession  of  motive  power  in 
addition  to  the  elevation  of  temperature  will  account  for 
the  fact  that  double  runs  were  secured  by  the  simple 
expedient  of  passing  the  dry  air  through  a  small  tank 
containing  only  5  cubic  feet  of  hot  water. 


VIII. 

ECONOMICAL  MODES  OF  COMPKESSIOX. 

IN  reference  to  the  most  economical  method  of  furn- 
ishing supplies  of  air  to  the  motor  tanks,  Mr.  E.  Hill, 
of  the  Norwalk  Iron  Co.,  who  has  had  very  extended 
experience,  gives  the  following  information  : — 

There  are  four  methods  in  all  of  charging  air  tanks. 

First.  A  reservoir  capacity  two,  three,  or  four  times 
the  size  of  the  tanks  and  containing  a  pressure  of  air 


ECONOMICAL   MODES   OF   COMPRESSION.  95 

much  greater  than  the  pressure  in  the  tank,  so  that 
when  the  valve  between  tank  and  stationary  reservoir  is 
opened  and. the  pressures  equalized,  the  Resulting  pressure 
in  the  tank  will  be  the  pressure  desired. 

Next.  Stationary  reservoirs  charged  to  a  pressure 
somewhat  higher  than  the  pressure  desired  in  the  tank 
and  said  stationary  reservoirs  brought  in  connection 
successively  with  the  tank  to  be  charged. 

Third.  A  reservoir  of  very  great  size  in  comparison 
with  the  size  of  tank  to  be  charged,  so  that  for  practical 
purposes  the  air  can  be  considered  as  being  drawn  .from 
a  reservoir  of  infinite  size. 

Fourth.     Direct  pumping  into  the  tank  itself. 

Referring  to  plan  No.  1,  we  have  considered  that  a 
reservoir  three  times  the  capacity  of  the  locomotive  tank 
is  employed.  This  reservoir  must  be  charged  to  a 
pressure  of  53.33  atmos.  in  order  that  the  pressure  in 
reservoir  and  tank  shall  be  42  atmos.  after  the  reservoir 
and  tank  have  equalized  their  pressures.  The  duty  then 
for  a  compressor  will  be  to  pump  up  that  tank  from  42 
atmos.  to  53J  atmos.  at  each  charging  of  the  locomotive. 
If  this  work  is  done  in  one  minute,  it  will  require 
2380  H.  P. 

Referring  to  plan  No.  2,  it  will  be  assumed  that  three 
stationary  reservoirs  are  used,  and  that  each  reservoir  is 
of  a  size  equal  to  the  size  of  the  tank  on  the  locomotive. 
If  these  three  reservoirs  are  charged  to  47  atmos.,  and 
reservoir  No.  ]  is  brought  into  connection  with  the  tank 
of  the  locomotive,  the  pressure  will  equalize  between  the 
two  and  become  27J  atmos.  If  now  No.  2  tank  is 
brought  in  connection,  the  pressure  will  become  37.25. 
If  the  third  reservoir  is  now  connected,  the  pressure  will 


96  STREET    RAILWAY    MOTORS. 

become  42.12  atmos.  Therefore,  the  duty  required  of 
the  compressor  is  to  pump  up  tank  No.  1  from  27J 
atmos.  to  47  atmos.,  tank  No.  2  from  37.25  tq  47  atmos., 
and  tank  No.  3  from  42.12  to  47  atmos.  This  will 
require  2119  H.  P.  if  done  in  one  minute. 

Referring  to  the  third  plan,  in  which  the  reservoir  is 
of  very  great  size,  so  that  practically  when  the  locomo- 
tive is  charged  there  is  no  fall  of  pressure,  the  duty  then 
of  the  compressor  is  to  compress  all  of  its  air  to  42  atmos. 
To  supply  the  locomotive  under  these  circumstances,  each 
minute  will  require  1828  H.  P. 

The  fourth  plan,  for  direct  pumping,  presumes  that 
absolutely  no  reservoir  at  all  is  used.  Here  the  duty 
is  simply  to  raise  the  pressure  in  the  locomotive  by 
direct  pumping  from  eight  atmos.  to  forty-two  atmos- 
pheres. This  will  require  1706  H.  P.  if  the  work  is 
done  in  one  minute. 

It  will,  of  course,  be  noticed  from  the  above  compari- 
sons that  the  fourth  plan  as  regards  power  is  by  all 
means  the  one  to  be  preferred  ;  but  it  is  not  presumed 
that  such  a  large  quantity  of  air  can  be  compressed  so 
quickly  and  cooled  so  rapidly  in  one  minute.  Therefore 
calculation  should  be  made,  if  a  locomotive  is  to  be 
dispatched  every  minute,  to  have  a  number  of  locomo- 
tives at  the  charging  station  at  the  same  time,  so  that 
each  of  those  locomotives  could  be  under  treatment  from 
ten  to  fifteen  minutes,  in  order  that  the  air  may  have 
time  to  cool  during  the  process  of  compression,  but  the 
total  power  will  be  such  as  to  dispatch  one  locomotive 
every  minute. 

Answering  other  questions  regarding  the  power  to  do 
the  above  work  in  2J,  5,  and  10  minutes,  it  may  be  said 


ECONOMICAL   MODES   OF   COMPRESSION.  97 

that  follows  in  inverse  proportion.  The  above  calcu- 
lations are  taken  at  a  mean  between  isothermal  and  adia- 
batic  compression,  and  are  as  near  as  possible  what  will 
be  actually  found  to  be  the  result  in  practice. 

As  regards  the  expense  of  running  compressors,  it  is 
proper  to  state  that  the  above  calculations  give  the  power 
in  H.  P.  The  expense  of  a  H.  P.  is  a  well-settled  matter 
according  to  the  style  of  engine  which  is  employed  to 
produce  it. 

FROST  FROM  EXPANSION  OF  AIR. 

It  is  a  common,  but  very  erroneous,  opinion  that  serious 
difficulty  is  experienced  in  compressed-air  engines  from 
the  intense  cold  produced  by  expansion  and  the  closing 
of  the  exhaust  passages  by  frost.  No  difficulty  of  the 
kind  has  ever  been  experienced  in  the  use  of  the  Hardie 
motor,  even  with  cold  air;  but  the  practice  of  reheating, 
which  should  never  be  omitted,  since  it  doubles  the  power 
at  nominal  cost,  raises  the  temperature  of  the  exhaust 
air  above  the  freezing-point.  In  the  tests  made  on  the 
Second  Avenue  Railroad  in  1879,  it  was  found  that, 
although  the  air  from  the  compressor  was  cooled  by 
passing  it  through  water,  there  was  no  deposit  of  frost. 
The  writer  explained  the  fact  on  the  theory  that  the 
capacity  of  air  for  moisture  was  not  increased  by  density, 
and  that  the  escaping  air  was  too  dry  to  deposit  moisture 
even  at  a  very  low  temperature.  Mr.  Hill,  of  Norwalk, 
confirms  this  opinion,  and  has  given  the  following  very 
satisfactory  explanation  : — 

"  Your  statement  regarding  the  water  left  in  compressed 
air  agrees  exactly  with  the  authorities  on  this  question 
7 


98  STREET   RAILWAY    MOTORS. 

as  we  understand  them.  The  density  of  the  air  does 
not  have  an  appreciable  effect  on  the  amount  of  moisture 
within  a  given  space.  The  temperature,  however,  aifects 
it  according  to  well-settled  results.  It  has  been  observed 
that  the  higher  that  air  pressures  have  been  the  less  lia- 
bility there  is  to  freezing  at  the  exhaust.  This  result  is 
in  opposition  to  the  preconceived  opinions  regarding  the 
use  of  compressed  air.  Air  of  15  to  30  Ibs.  pressure 
when  expanded  in  an  engine  almost  uniformly  gives 
trouble  at  the  exhaust.  Therefore  it  has  been  argued 
that  air  at  very  high  pressure — several  hundred  pounds — 
would  give  a  proportionate  amount  of  trouble  there, 
freezing  because  its  exhaust  could  be  expected  to  be  so 
very  much  colder  than  the  exhaust  of  air  of  lighter 
pressure ;  but,  as  I  have  stated  above,  it  has  been  found 
that  the  air  at  high  pressure  does  not  give  this  antici- 
pated trouble,  and  in  fact  does  not  give  as  much  trouble 
as  does  air  at  lower  pressure.  The  reason  for  this  is 
readily  explained.  Air  at  the  low  pressure,  when  it  is 
exhausted,  will  be  cold  enough  to  freeze  whatever  moisture 
there  may  be  in  it.  Air  at  the  high  pressure  will,  of 
course,  be  cold  enough  on  exhaust  to  freeze  the  moisture 
that  may  be  in  it.  But  to  get  the  same  power  from  low- 
pressure  air  as  we  can  get  from  high-pressure  air,  we 
must  use  of  the  low-pressure  air  very  many  more  cubic 
feet.  As  when  temperatures  are  equal  the  moisture  in 
the  air  depends  upon  the  volume,  it  follows  that  for  a 
given  power  when  obtained  from  low-pressure  air  we 
have  passed  through  our  engine  much  more  moisture, 
and,  as  it  all  freezes  in  any  event,  we  run  a  greater  risk 
of  being  stopped  at  the  exhaust.  Taking  another  case 
where  air  at  600  Ibs.  pressure  is  stored  in  the  reservoir 


ECONOMICAL   MODES   OF   COMPRESSION.  99 

of  a  pneumatic  locomotive  and  is  then,  through  a  re- 
ducing valve,  drawn  down  to  100  Ibs.  pressure  for  use 
jn  the  cylinders,  we  would  find  that  the  air  at  100  Ibs. 
pressure  would  be  only  J  saturated  with  moisture.  The 
air  at  600  Ibs.  pressure  would  be  fully  saturated.  The 
moisture  in  one  cub.  ft.  of  600  Ibs.  air  being  by  the  process 
of  reduction  distributed  through  six  cub.  ft.  of  100  Ibs. 
pressure,  the  result  is  that  the  air  of  100  Ibs.  pressure  is, 
as  stated  above,  only  ^  saturated.  Or,  stating  the  case 
in  another  way,  a  cubic  foot  of  air  at  100  Ibs.  pressure 
which  has  been  obtained  from  a  tank  holding  600  Ibs. 
of  air  would  contain  only  ^  the  moisture  which  would 
be  found  in  a  cub.  ft.  of  air  at  100  Ibs.  pressure,  which 
had  been  obtained  by  compressing  atmospheric  air  to 
100  Ibs.  pressure. 

"  The  above  statements  would  all  hold  true  without 
regard  to  the  method  of  cooling.  The  question  only 
would  be,  what  is  the  temperature  of  the  air,  and  has  it 
been  quiescent  long  enough  to  allow  the  moisture  to  be 
dropped  ?  The  statement  which  I  have  heard  made,  that 
blowing  air  through  water  dried  it  by  reason  of  the 
affinity  of  the  water  for  the  moisture  in  the  air,  is,  in  my 
opinion,  a  lame  explanation.  The  process  dries  the  air 
simply  because  it  cools  it,  and  any  other  method  of  cool- 
ing would  accomplish  exactly  the  same  result." 

Considerable  space  has  here  been  given  to  the  subject  of 
compressed  air  as  a  propelling  power  on  street  railroads, 
for  the  reason  that  writers  who  treat  upon  the  subject  of 
street  motors  almost  invariably  pass  it  over  with  a  few 
disparaging  remarks  as  something  that  has  been  tried  and 
found  wanting.  It  is  really  amazing  to  find  so  vast  an 
amount  of  ignorance  accumulated  on  this  subject.  The 


100  STREET    RAILWAY   MOTORS. 

reasoning  seems  to  be  :  "Well,  this  thing  has  been  tried  ; 
if  it  had  any  merit,  why  was  it  abandoned  ?  And  no 
trouble  is  taken  to  inquire  into  the  merits  of  the  motor, 
or  the  causes  which  prevented  its  general  use, — causes 
having  no  connection  whatever  with  the  merit  or  the 
practicability  of  the  invention.  If  the  facts  that  have 
been  stated  will  lead  intelligent  engineers  and  capitalists 
to  investigate,  there  will  soon  be  a  change  of  public  opin- 
ion upon  this  subject,  and  the  best  of  all  modes  of  pro- 
pulsion for  street  service  will  not  be  cast  aside  for  other 
systems  far  more  expensive  in  plant  and  operation,  and 
far  less  satisfactory  in  results,  both  to  the  public  and  to 
capitalists. 


IX. 

COST  OF  OPERATION  OF  THE  COMPRESSED  AIR 
MOTOR  FOR  ONE  DAY— SIX  MILES  DOUBLE 
TRACK. 

FOR  the  determination  of  this  question  the  data  can 
be  relied  upon  with  more  confidence  than  in  any  of  the 
other  cases  under  consideration. 

It  has  been  demonstrated  that  the  motor  can  be  run 
with  300  cubic  feet  of  free  air  per  mile,  and  that  the 
compressor  plant  to  furnish  this  volume  of  air  for  each 
of  60  motors  will  require  not  more  than  600  horse- 
power, or  10  horse-power  at  the  central  station  for  each 
motor.  Each  horse-power  requires  2}  Ibs.  per  hour  of 
$3  coal,  so  that  the  coal  per  motor  per  hour  will  be  25 


COST    OF    COMPRESSED    AIE   MOTOR.  101 

pounds,  to  which  the  equivalent  of  3  pounds  must  be 
added  for  reheating,  making  28  Ibs.  per  hour  for  a  run 
of  6  miles.  The  consumption  per  mile  run  will,  there- 
fore, be  4f  pounds,  and  the  cost  7  mills  per  mile  run. 

This  is  the  whole  cost  of  fuel,  not  including  interest 
and  repairs,  which  are  less  than  in  other  systems. 

Cost  of  Plant  and  of  Operation  for  the  Pneumatic  Motor. 

Land,  22,000  square  feet  of  ground,  at  $1.50     .  $33,000 

Building 80,000 

Engine,  boiler,  setting,  etc.,  for  600  H.  P.           .  30,000 

Reservoirs,  pipes,  etc.        .....  5,000 

Cost  for  six  miles  double  track  .         .         .     $148,000 

Street  Construction — One  Mile,  Double  Track. 

Track $20,000 

Paving,  9282  square  yards,  at  $3      .         .         .         27,846 

Total  street  construction     ....         47,846 
Cost  for  six  miles $287,076 

Equipment. 

75  combination  cars  and  motors,  at  $3500          .     $262,500 

Summary. 

Power-house  and  plant $148,000 

Street  construction 287,076 

Equipment         .         .         .         .         .         .         .  262,500 

Engineering,  legal  and  miscellaneous  expenses  20,000 

$717,576 


102  STREET    RAILWAY    MOTORS. 

Cost  of  Operation  of  Six  Miles  Double  Track  for  One 
Day  with  the  Pneumatic  Motor. 

Coal,  5760  miles  run  at  4§    pounds   per    mile — 

131  tons,  at  $3  per  ton            ....  $40.50 

Water,  oil,  and  grease           .....  6.50 

Depreciation  of  plant  and  rolling-stock         .         .  78.00 

60  Conductors,  at  $2 120.00 

60  Drivers,  at  $1.75 105.00 

Engineers  and  firemen  at  station           .          .          .  25.00 

Car-house  and  other  service          ....  28.00 

Repair  of  motors  and  cars     .....  200.00 

Repair  of  engines  and  compressors         .          .         .  15.00 

Repair  of  track  and  buildings       ....  50.00 

Track  cleaning,  train,  and  shop  expenses    .          .  25.00 

Accidents      .                   20.00 

Legal  and  other  expenses     .....  10.00 

General  and  miscellaneous  expenses     .          .         .  50.00 

$773.00 

Cost  per  mile  .          .         .  13.42  cents. 

Of  this  amount  the  fuel  alone  costs  7  mills. 


COMPRESSED  AIR  FOR  ELEVATED  RAILROADS. 

The  practicability  of  using  compressed  air  instead  of 
steam  on  elevated  railroads  and  its  superior  economy 
were  fully  demonstrated,  in  1880,  on  the  Second  Avenue 
Railroad,  in  New  York. 

A  motor  was  constructed  at  the  Baldwin  Locomotive 
Works,  upon  the  plans  and  under  the  immediate  super- 
vision of  Robert  Hard ie,  and  was  tested  upon  the  Second 
Avenue  Railroad  ;  certificates  of  these  tests  by  prominent 
officers  and  machinists  of  the  road  are  in  possession  of 
the  writer. 

The  section  of  the  road  upon  which  the  experiments 


COST   OF   COMPRESSED    AIR   MOTOR.  103 

were  conducted  is-8J  miles  long,  and  there  are  22 
stations  in  this  distance.  The  road  is  undulating  and 
circuitous ;  an  elevation  of  80  feet  has  to  be  overcome 
in  a  part  of  the  distance,  and  6  quarter- circle  curves  of 
90  feet  radius.  Intervals  between  trains,  3  minutes. 

A  report  by  Charles  W.  Potter,  in  1883,  gives  a  very 
full  account  of  the  test  of  the  Hardie  motor  on  the  ele- 
vated road  and  its  economic  results.  An  extract  is  here 
given  : — 

"The  Hardie  engine,  weighing  18f  tons,  was  found 
capable,  with  a  single  charge  of  air,  of  hauling  the  regu- 
lation five  car  trains,  full  of  passengers  (weighing 
approximately  60  tons,  or  about  78  -tons  including  the 
engine),  the  entire  distance  of  the  road,  making  all 
regulation  stops  to  deliver  and  receive  passengers,  ac- 
complishing the  trips  in  the  schedule  time,  and  with 
sufficient  surplus  of  air  remaining  to  enable  it  to  return 
light  to  the  engine  depot,  a  distance  of  5J  miles,  the 
greater  part  up  hill.  The  quantity  of  air  expended  in 
making  these  trips  with  trains  was  equal  to  12,600 
cubic  feet  at  atmospheric  pressure,  and  in  returning 
light,  4600  cubic  feet ;  making  a  total  expenditure  of 
17,200  cubic  feet.  It  may  be  mentioned  that  this  dis- 
tance is  the  utmost  which  the  present  steam  locomotives 
travel  without  a  fresh  supply  of  water. 

"  The  efficiency,  and  still  more  the  economy,  of  an  air 
locomotive  increases  with  the  magnitude  of  the  scale  on 
which  it  is  constructed  :  and  therefore,  as  the  engine 
whose  performances  are  given  was  built  for  experiments 
on  the  elevated  railroad,  and  was  necessarily  limited  in 
weight,  it  is  clear  that  were  it  possible  to  increase  the 
weight  to  30  or  35  tons,  as  would  probably  be  the  case 


104  STREET   RAILWAY    MOTORS. 

in  an  underground  railway,  the  storage  capacity  for  air 
would  be  increased  and  a  proportionately  longer  distance 
would  be  possible  with  a  single  change. 

"  Moreover,  the  weight  of  the  London  underground 
trains,  in  proportion  to  the  weight  of  the  engines  that 
draw  them,  is  less  than  in  the  case  of  the  elevated  trains 
in  New  York,  and,  as  the  stations  are  farther  apart,  still 
better  results  may  be  expected.  In  fact,  it  is  urged  that 
in  point  of  efficiency  air  engines  of  the  Hardie  type  can 
be  constructed  to  meet  all  the  requirements  of  every 
portion  of  an  underground  as  well  as  of  an  elevated  rail- 
way even  better  than  steam,  for  the  pure  air  discharged 
at  each  revolution  will  also  aid  in  ventilation. 

"The  next  and  most  important  consideration  is  the 
cost,  first  of  equipping  the  road,  and  secondly  of  operat- 
ing it,  and  as  in  this  particular  it  would  be  well  to  have 
all  estimates  on  actual  experiment,  it  is  desirable  to  again 
revert  to  the  results  attained  upon  the  elevated  railroads 
in  order  to  make  a  comparison  with  the  steam  engines 
there  in  use. 

"As  the  storage  reservoirs  used  in  air  locomotives  are 
cheaper  to  construct  than  the  boilers  of  steam  locomo- 
tives, and  as  the  machinery  in  the  one  case  entails  prac- 
tically no  more  complication  than  in  the  other,  it  is 
clear  that  in  point  of  first  cost  the  balance  is  in  favor  of 
the  compressed  air  locomotive  ;  but  the  margin  of  saving 
is  rather  more  than  counterbalanced  by  the  compressing 
plant  necessary  for  furnishing  the  air.  The  builders  of 
compressing  machinery  in  the  United  States  estimate 
that  to  furnish  12,600  cubic  feet  of  free  air  (the  quantity 
expended  by  the  Hardie  engine  in  a  single  trip)  com- 
pressed to  600  pounds  per  square  inch,  which  was  the 


COST   OF   COMPRESSED    AIR    MOTOE.  105 

storage  pressure  adopted  in  the  engine  now  under  con- 
sideration, and  to  furnish  this  supply  every  three  minutes, 
the  amount  of  horse-power  required  is  1285,  and  they 
are  willing  to  guarantee  the  correctness  of  this  estimate, 
and  contract  for  the  supply  of  the  necessary  plant. 

"As  the  locomotives  used  have  to  be  supplied  with  air 
at  each  end  of  the  road,  this  amount  of  power  must 
be  duplicated  ;  hence  a  total  is  necessary  of  2570  horse- 
power, or  say  roundly  2600,  to  operate  the  particular 
section  of  the  road  referred  to.  On  the  whole,  therefore, 
the  first  cost  of  equipping  the  road  might  be  somewhat 
greater  for  air  than  for  steam  locomotives ;  but  this,  as 
will  be  shown  later,  would  be  more  than  counterbalanced 
by  the  reduced  cost  of  operating.  As  it  requires  at  least 
36  locomotives  to  carry  on  this  traffic,  at  three  minute 
intervals,  including  switching  and  relays,  each  locomo- 
tive would  be  represented  by  about  72  horse-power  of 
stationary  plant,  and  this  is  the  maximum  that  would 
be  needed,  as  it  is  only  during  a  few  hours  morning 
and  evening  that  the  interval  between  trains  is  so  short 
as  three  minutes,  and  as  it  is  obviously  expedient  to 
divide  up  the  power  into,  say,  four  complete  sets  at  each 
terminus,  it  would  only  be  necessary  to  operate  the 
whole  of  it  during  those  few  hours,  and  thus  ample 
opportunity  would  be  afforded  for  inspection  and  repairs. 

"  Strange  as  it  may  seem  at  first  sight,  considering  that 
the  power  is  used  second-hand,  so  to  speak,  yet  a  very 
large  saving  is  effected  in  point  of  fuel,  and  it  is  this 
saving,  with  that  of  the  fireman  on  the  locomotive,  that 
turns  the  balance  of  economy  greatly  in  favor  of  com- 
pressed air.  The  cost  of  operating  is  computable  as 
follows : — 


106  STREET   RAILWAY    MOTORS. 

"  The  average  rate  of  consumption  in  these  steam  loco- 
motives is  one  ton  per  60  train-miles,  or  about  45  pounds 
per  mile.  This  is  necessarily  high,  owing  to  the  frequent 
stoppages.  As  previously  stated,  2600  horse-power  will 
charge  a  locomotive  with  compressed  air  every  1J 
minutes,  or  40  locomotives  per  hour,  and  each  locomo- 
tive will  haul  a  train  8J  miles,  being  340  train-miles 
per  hour.  The  stationary  compressing  engines  need  not 
consume  more  than  2  Ibs.  of  coal  per  horse-power  per 
hour,  or  say  2  J  Ibs.  to  make  allowances  and  be  on  the 
safe  side.  Hence  the  consumption  of  fuel  for  2600  H.  P. 
will  be  6500  Ibs.  per  hour,  and  6500  Ibs.  over  340  miles 
equals  less  than  20  Ibs.  per  train-mile,  not  half  the  con- 
sumption of  the  steam  locomotives,  and  only  one-fourth 
the  cost,  as  cheaper  fuel  may  be  used.  Again,  as  the 
air  locomotives  require  only  one  man  to  drive  them,  a 
considerable  saving  in  the  cost  of  labor  is  effected,  even 
allowing  for  the  comparatively  small  attendance  neces- 
sary to  work  the  stationary  plant." 

In  the  figures  given  by  Mr.  Potter,  he  estimated  a 
saving  of  17  pounds  of  coal  per  train-mile  and  340  train- 
miles  per  hour.  If  this  average  should  be  maintained 
for  only  12  hours,  allowing  for  longer  intervals  at  mid- 
night and  in  the  middle  of  the  day,  the  saving  of  fuel 
would  be  5780  Ibs.,  or  2.89  tons  per  hour,  34J  tons  per 
day,  and  22,592  tons  per  annum,  costing  in  the  tender 
of  engine  probably  $5  per  ton,  or  $112,960  per  year, 
the  interest  at  5  per  cent,  on  $2,259,200. 

But  this  is  not  all.  The  36  engines  require  firemen, 
and  deducting  11  to  offset  labor  at  the  compressor  plant, 
there  will  remain  25  men  at  $1.75  per  day.  This  small 


COST    OF    COMPRESSED    AIR   MOTOR.  107 

item  amounts  to  $16,000  a  year,  the  interest  on  $320,000 
at  5  per  cent. 

What  would  be  the  cost  of  the  compressor  plant  to 
furnish  1 2,600  cubic  feet  of  free  air  in  1 J  minutes  =  8400 
cubic  feet  per  minute?  The  compressors,  boilers,  and 
engines  can  all  be  covered  by  $115,000,  so  that  the 
saving  in  firemen  alone  would  represent  nearly  three 
times  the  cost  of  the  compressor  plant. 

How  can  there  be  any  question,  therefore,  as  to  the 
great  superiority  of  compressed  air  over  steam  for  the 
operation  of  city  railroads,  whether  surface,  elevated,  or 
underground  ? 

WHY  COMPRESSED  AIR  is  NOT  IN  GENERAL  USE. 

If,  as  stated,  it  has  been  demonstrated  by  actual 
results,  both  on  surface  and  elevated  railroads,  that  com- 
pressed air  furnishes  a  mode  of  propulsion  far  superior 
to  steam  or  horse- power  and  at  the  same  time  far  more 
economical,  affording  superior  public  accommodation 
and  larger  dividends  to  the  companies,  requiring  no 
trolley  wires  overhead,  or  cables  beneath  the  surface,  with 
not  a  single  objectionable  feature  of  any  description,  but 
many  in  its  favor,  why  is  not  the  system  universally 
used  ?  The  question  is  pertinent,  and  the  answer  can  be 
briefly  given. 

In  1879  public  opinion  was  not  sufficiently  educated 
to  regard  this  improvement  with  favor.  Absurd  as  the 
objection  then  made  may  now  appear,  presidents  of  horse 
railroad  companies  declared  that  any  car  moving  along 
a  street  without  horses  in  front  would  frighten  other 
horses  even  if  there  was  no  noise,  and  that  many  acci- 


108  STREET    RAILWAY    MOTORS. 

dents  would  occur  and  suits  for  damages  be  instituted  ; 
that  the  system  could  not  be  used  without  stuffing  the 
skins  of  dead  horses  and  running  them  on  a  low  truck  in 
front.  This  was  the  reason  given  to  the  writer  by  the 
president  of  a  city  railroad  in  Philadelphia,  who  declined 
to  consider  the  question  of  the  advantages  of  a  change  of 
system,  and  attempts  to  induce  others  to  examine  into 
the  merits  of  compressed  air  proved  equally  unsuccessful, 
so  that  efforts  were  discontinued. 

When  it  is  considered  that  both  cable  and  electric 
roads  run  without  horses  and  cause  far  more  noise  than 
the  pneumatic  engine,  the  objections  made  in  1879  ap- 
pear very  absurd. 

But  this  was  not  the  only  cause  of  failure  to  secure 
the  adoption  of  the  improvement.  Mr.  Hardie  unfortu- 
nately fell  into  the  hands  of  irresponsible  parties  and 
parted  with  the  control  of  his  patents  to  a  straw  com- 
pany, the  collapse  of  which  put  an  end  to  further  efforts. 
Mr.  Hardie  afterwards  accepted  a  position  as  superin- 
tendent of  a  locomotive  works,  and  has  recently  filled 
the  position  of  mechanical  engineer  of  the  Columbian 
Exposition  at  Chicago.  The  following  is  his  own  story 
of  the  causes  of  failure  in  the  introduction  of  the  pneu- 
matic motors  : — 

"  The  proper  way  to  have  met  all  objections  was  not 
by  discussion  and  argument,  but  by  a  practical  demon- 
stration. Railroad  men  were  not  satisfied  with  a  few 
exhibition  trips  of  the  motors,  although,  as  a  general 
rule,  the  performance  was  considered  very  satisfactory 
so  far  as  it  went ;  but  they  all  wanted  to  see  a  railroad 
operated  exclusively  and  successfully;  and  until  then 
no  railroad  would  adopt  the  system.  As  it  required 


COST   OF   COMPRESSED    AIR    MOTOR.  109 

capital  to  do  this,  and  as  the  motor  company  had  prac- 
tically none,  the  enterprise  was  never  carried  beyond 
the  experimental  stage.  It  is  true  that  this  company 
was  capitalized  at  $1,000,000,  but  that  needs  explana- 
tions. Those  who  organized  the  company  were  men  of 
no  financial  standing,  and  the  stock  was  all  issued  to 
them,  without  payment  or  consideration,  except  the  ex- 
penses of  organization  and  a  few  preliminary  tests.  In 
order  to  evade  the  law  which  required  that  the  stock  should 
be  paid  for  at  its  full  par  value,  a  valuation  of  $1,000,000 
was  put  upon  some  patents  which  one  of  their  number 
held  in  trust;  and  the  stock  was  issued  to  him  in  con- 
sideration of  said  $1,000,000  worth  of  patents:  said 
trustee  then  divided  the  stock,  as  previously  understood 
and  agreed  on,  including  a  small  percentage  to  the 
patentees.  In  order  to  provide  i  working  capital/  the 
stockholders  assessed  themselves  in  a  percentage  of  their 
stock,  which  was  set  aside  as  '  treasury  stock/  to  be  dis- 
posed of  at  whatever  price  it  could  be  sold  for.  In  this 
way  some  money  was  raised,  but  not  enough  to  do  any 
real  business,  and  consequently  nothing  was  done  beyond 
making  exhibition  runs  of  the  motors,  and  getting  flour- 
ishing accounts  into  the  newspapers,  on  the  strength 
of  which  the  individual  members  '  peddled '  their 
stocks. 

"  Among  those  who  bought  stock  was  a  gentleman  of 
means,  as  well  as  culture  and  refinement,  and  strict 
integrity.  In  some  way  he  was  induced  to  loan  the 
company  money  from  time  to  time  on  its  notes,  and  this 
kept  it  alive  a  while  longer.  Indeed  it  began  to  look  as 
if  some  real  business  might  be  done  after  all.  A  com- 
pressed-air locomotive  was  built  and  tested  on  the 


110  STEEET   RAILWAY   MOTORS. 

elevated  railroad,  which  succeeded  in  hauling  their  four- 
car  trains,  loaded  with  passengers,  the  whole  length  of 
the  road  ;  making  all  the  stops  to  receive  and  deliver 
passengers,  making  the  schedule  time,  and,  in  fact,  doing 
practically  everything  which  the  steam  locomotives  were 
required  to  do.  At  the  end  of  the  trip  it  was  found  that 
a  sufficient  surplus  of  compressed  air  remained  in  the 
reservoirs  to  insure  against  possible  failure  ;  and,  as  will 
be  shown  later,  the  economy  was  beyond  question.  For 
some  unexplained  reason,  however,  this  success  was  not 
followed  up,  and  eventually  a  sudden  and  complete  col- 
lapse was  brought  about  by  the  sudden  and  sad  death 
of  the  gentleman  referred  to,  in  whose  estate  the  com- 
pany's overdue  notes  were  found. 

"  The  inside  workings  and  manipulations  of  this  straw 
company,  with  paper  capital,  would  make  interesting 
reading ;  but  I  trust  enough  has  been  said  in  the  brief 
space  allowable  here  to  show  that  it  was  not  an  organi- 
zation well  calculated  to  make  a  commercial  success  of 
such  an  undertaking,  and  is  my  explanation  for  the 
project  being  abandoned.  Needless  to  say,  it  was  a  great 
disappointment  to  me.  Those  desiring  to  investigate 
further  can  be  furnished  with  plenty  of  evidence  as  to 
the  practical  utility  of  the  system,  and  the  mechanical 
success  of  the  experimental  motors." 

Notwithstanding  the  success  of  the  air  motor  on  the 
Second  Avenue  Elevated  Railroad  and  the  favorable  in- 
dorsement of  the  officers  who  made  the  tests,  the  directors 
were  not  inclined  to  incur  at  that  time  the  expense  of  a 
change  of  plant,  and  the  death  of  the  capitalist  who  had 
advanced  the  money  for  the  construction  of  the  motor 
caused  the  abandonment  of  further  efforts.  It  was  in 


OTHER   AIR   MOTORS.  Ill 

fact  impossible  for  Mr.  Hardie  to  take  another  step,  as 
he  had  parted  with  his  patents  for  a  stock  consideration 
which  proved  to  be  worthless,  and  the  company  had  hy- 
pothecated these  patents,  which  were  its  only  assets,  for 
loans  that  they  were  unable  to  pay. 

Mr.  Hardie  has  prepared  new  plans  with  valuable  im- 
provements, the  old  patents  have  nearly  all  expired,  and 
the  way  is  open  for  the  introduction  of  air  motors  with- 
out fear  of  annoyance  by  hostile  litigation. 


X. 

OTHER  AIR  MOTORS. 

THE  newspapers  from  time  to  time  publish  notices 
of  new  motors  which  have  a  very  brief  existence  and 
never  pass  the  experimental  stage. 

Some  of  these  have  been  misnamed  compressed  air 
motors,  but  the  air,  instead  of  being  applied  to  operate  a 
piston  in  a  metal  cylinder,  is  used  to  communicate 
motion  to  some  intermediate  machinery,  and  the  action 
depends  upon  the  application  of  principles  essentially 
different  from  those  that  have  been  utilized  in  the  com- 
pressed air  motors  of  Hardie  and  Mekarski. 

In  one  of  these  proposed  systems  a  line  of  pipes  about 
6  inches  in  diameter  was  laid  under  ground  in  the 
middle  of  the  track  and  rotated  by  steam,  compressed 
air,  or  other  power.  An  arm  like  the  arm  of  a  cable- 
grip  car  passed  through  a  slot,  like  the  slot  of  a  cable- 
line,  and  carried  small  wheels  which  could  be  changed 


112  STREET    RAILWAY    MOTORS. 

in  position  at  the  pleasure  of  the  motor-man,  and  the 
rotation  of  which  by  contact  with  the  revolving  pipe 
communicated  motion  to  the  car.  The  speed  was  regu- 
lated by  varying  the  angle  at  which  the  small  revolving 
wheels  were  set.  After  an  expenditure,  it  is  said,  of 
many  thousands  of  dollars,  this  device  proved  a  failure, 
and  has  been  abandoned. 

Nearly  half  a  century  ago  the  engineering  profession 
was  entertained  with  occasional  notices  of  a  so-called 
atmospheric  railway,  which  consisted  of  a  pipe  36  inches, 
more  or  less,  in  diameter,  laid  under  ground.  On  the 
top  was  a  continuous  slot,  2  inches  wide,  covered  by  a 
flap-valve  of  leather,  rubber,  or  other  elastic  material. 
Inside  the  pipe  was  a  piston  carrying  an  arm  through 
the  slot  like  the  arm  of  the  grip  in  a  cable-car.  By 
exhausting  the  air  in  front,  the  atmospheric  pressure 
behind  would  communicate  motion  to  the  piston,  and  as 
it  moved  the  arm  would  open  the  flap-valve,  which 
would  close  again  behind  it  as  it  passed.  A  trial  of  this 
plan  was  made  about  1840,  on  the  West  London  Rail- 
way, and  also  on  one  or  two  other  railways,  but  all  were 
soon  abandoned  as  unsatisfactory. 

The  result  of  these  trials  clearly  proved  that  the 
atmospheric  railway  system  could  not  stand  in  competi- 
tion with  that  of  the  locomotive  engine,  unless  in  some 
peculiar  situations.  Chambers's  Encyclopedia  refers  to 
this  contrivance,  and  states  that  the  expense  and  care 
necessary  to  keep  the  tube  with  its  valve  in  good  work- 
ing order  led  to  the  removal  of  the  atmospheric  me- 
chanism from  the  various  railways  on  which  it  was 
established,  so  that  the  history  of  atmospheric  railways 
may  be  ranked  under  the  chapter  of  failures.  They 


CABLE    AND   ELECTRIC   ROADS.  113 

survive  only  in  the  form  of  pneumatic  dispatch  tubes 
for  the  conveyance  of  parcels,  many  of  which  are  used 
in  London. 

After  fifty  years,  and  in  the  face  of  this  experience,  it 
is  calculated  to  promote  a  smile  to  read  a  notice  in  the 
papers  of  "A  New  Motor"  and  of  the  existence  of  a 
pneumatic  power  and  motor  company,  which  has  re- 
vived the  old  atmospheric  railway  scheme,  with  the 
difference  that,  instead  of  the  continuous  slot  and  elastic 
flap-valve,  the  slot  is  covered  by  a  continuous  row  of 
rigid  slide-valves,  which  are  opened  by  a  projection  in 
the  power-bar  as  the  piston  passes  along  the  tube,  and 
closed  by  a  similar  device  after  its  passage.  There  is 
no  reason  to  believe  that  this  device  can  be  more 
effective  than  the  old  flap- valve  ;  but,  on  the  contrary, 
must  be  more  difficult  and  expensive  to  construct  and 
maintain,  and  the  loss  by  leakage  in  a  continuous  line 
of  valves  must  be  excessive. 


XT. 

CABLE    AND  ELECTRIC   ROADS. 

CABLE  and  electric  roads  are  too  well  known  to  re- 
quire any  description.  Many  publications  have  been 
made,  giving  details  of  construction  and  explanation  of 
principles,  which  would  be  entirely  out  of  place  in  this 
volume,  the  object  of  which  is  chiefly  to  institute  a  com- 
parison between  the  different  systems  now  in  use,  or 
proposed  to  be  introduced,  as  to  cost  of  plant  and  of 


114  STREET    RAILWAY    MOTORS. 

operation,  and  the  general  results  that  would  follow 
their  adoption,  as  regards  dividends  upon  capital  and 
public  accommodation. 

In  the  attempt  to  institute  such  comparisons,  great 
difficulties  are  experienced  from  the  unreliable  character 
of  the  data  furnished  in  public  reports.  There  has  been 
no  uniform  system  of  keeping  accounts.  Items  of  ex- 
pense are  sometimes  included  in  one  report  and  omitted 
in  another ;  in  some,  interest  will  be  included  and  in 
others  excluded.  The  cost  of  plant  varies  greatly  in 
different  localities,  and  includes  items,  some  of  which 
are  independent  of,  and  others,  in  part,  at  least,  propor- 
tioned to  the  length  of  road  operated. 

Comparative  estimates,  to  be  of  any  value,  or  inspire 
any  confidence  in  the  results,  must  be  based  upon  similar 
conditions  as  to  the  character  of  the  work,  the  length  of 
line  operated,  and  the  volume  of  traffic. 

As  the  data  furnished  by  census,  State,  and  other 
reports  apply  to  roads  of  diverse  lengths,  characters,  and 
conditions,  an  attempt  will  be  made  to  take  differences 
into  consideration  and  make  comparisons  as  fairly  as  pos- 
sible on  a  basis  of  uniformity.  For  this  purpose  a  num- 
ber of  miscellaneous  results  and  data  will  be  given,  and 
an  estimate  then  attempted  of  the  cost  of  plant  and 
working  of  a  road  of  given  length  and  given  volume 
of  business  operated  by  each  of  the  systems  proposed  to 
be  compared.  When  it  is  considered  that  the  reported 
cost  of  plant  per  mile  on  one  road  may  be  three  or  four 
times  as  much  as  on  another,  and  that  reported  earnings 
and  expenses  vary  as  one  to  two  or  more,  the  necessity 
of  some  uniform  basis  of  comparison  will  be  obvious. 


CABLE    AND    ELECTRIC    ROADS.  115 

It  is  proper,  therefore,  to  assume  uniform  conditions, 
and  a  road  will  be  taken  six  miles  long  in  a  paved  city, 
laid  in  substantial  manner,  with  double  track,  heavy 
rails,  a  volume  of  business  sufficient  to  require  one  16- 
foot  standard  car  every  two  minutes  for  an  average  of 
16  hours.  Horse-cars  making  4  miles  per  hour,  and 
motors  6  miles,  and  a  reserve  of  20  per  cent,  of 
horses,  cars,  and  motors  for  extra  service  and  contin- 
gencies. This  will  require  72  cars  for  the  motor  lines 
and  108  for  horse  lines,  and,  for  the  sake  of  uniformity, 
the  equipments  will  be  supposed  to  be  combinations  of 
car  and  motor  in  one,  and  having  the  usual  seating 
capacity  for  20  passengers.  Such  cars  can  be  used  with 
all  motors,  except  steam  and  gas,  where  separate  motors 
will  be  required.  The  daily  car  mileage  with  the  data 
given  will  be  5760  miles,  and  the  annual  mileage 
2,102,400.  The  combination  motor  should  have  power 
sufficient  to  haul  on  ordinary  roads  one,  and  on  level 
roads  two,  trailers  to  meet  the  requirements  of  maximum 
business. 

To  realize  how  little  information  can  be  derived  from 
reports  as  to  actual  cost  and  expenses,  where  dissimilar 
conditions  are  not  recognized,  the  following  extract  will 
be  given  : — 

From  Chicago  Street  Railway  Journal,  November, 
1892,  article  by  Mr.  M.  Eamsay,  chairman  of  com- 
mittee, after  correspondence  with  every  cable  road  in 
the  United  States,  and  with  the  representative  electric 
and  horse  railroads  : — 


116  STREET    RAILWAY    MOTORS. 

Operating  Statistics  of  Eight  Gable  Roads. 


Maximum.    Minimum. 

Average. 

No.  of  grip  cars  daily       .         .  193                 5 

50 

"      trail    "                    .            298                5 

74 

Daily  mileage  grip  cars,  each  .  127               70 

98 

trail    "       "       .  123              70 

95 

Receipts   per  car-mile,  includ- 

ing mileage  of  trail  cars        .     29.84        15.10 

20.20 

Gross    operating  expenses   per 

car  mile,   exclusive   of   fixed 

charges           .         .         .         .41.00           6.75 

16.70 

Net  earnings  per  car-mile         .       8.4            4.9 

6.97 

For  Seven  Electric  Roads. 

Maximum.    Minimum. 

Average. 

Motor  cars  daily       .         .         .280                5 

57 

Trail      "                    ...       5                4 

41 

Daily  mileage,  motor         .         .   127               70 

101 

"           "         trail  .         .         .120              56 

88 

Receipt  per  car-mile,  including 

mileage  of  trail  cars     .         .     40.28         13.5 

24. 

Gross  operating    expenses   per 
car-mile        ....     25.44          9.0 

12.5 

Net  earnings  per  car-mile          .     14.34          0.0 

6.04 

Notes  from  Street  Railway  Journal  of  July 

,  1892.— 

Ten  Cable  Roads. 

Maximum.   Minimum.    Average. 

Length  of  line         .         .         .       11.69           2.70 

7.32 

Length  of  all  tracks        .         .       23.38           5.44 

14.29 

Number  of  grip  cars       .         .     116              12 

60 

trail  "                         380                8 

102 

Indicated   horse-power  of  en- 
gines   3400  200          1329 

Cost  per  mile  of  line       ..       $683,840  $159,227    $290,940 


CABLE   AND    ELECTRIC   ROADS.  117 

Ten  Electric  Roads. 

Maximum.  Minimum.    Average. 

Length  of  line         .  .  .       11.71  2.80  5.56 

"         all  tracks  .  .       16.35  2.80  6.72 

Number  of  motor  cars                     47  2  12 

"           tow  cars                         15  2  4 

Indicated  horse-power  .  .    1050  35  237 

Cost  per  mile  of  line  .  .$98,749  $8,807  $36,145 

Ten  Cable  Roads — Twelve  Months'1  Operation. 

Maximum.     Minimum.      Average. 

Car  mileage    ....  6,290,172      310,331     2,327,625 

Passengers  carried  .         .         36,218,807  1,340,820  10,199,569 

Passengers  per  mile  operated  4,261,036      437,628     1,355,965 

Operating  expenses  per  car  mile      21.91  cts.     9.39  cts.     14.12  cts. 
"  "  per  passenger    4.28    "       2.43    "        3.22  " 

1242  standard  car-miles  per  mile  of  line  is  an  average 
of  daily  operation  of  cable  lines. 

A  comparative  estimate  of  cable  and  electric  roads,  of 
equal  capacity,  gives  nearly  equal  cost  per  mile.  The 
cables  are  generally  metropolitan  and  the  electric  sub- 
urban. 

Ten  Electric  Roads. 

Maximum.  Minimum.       Average. 

Car  mileage         .         .         ."                702,770  19,754       244,210 

Passengers  carried      .         .         .     2,752,382  60,217       803,121 

"              "      per  mile          .        470,090  14,795       222,645 

Operating  expenses  per  car  mile        36.04  cts.  8.34  cts.  13.21  cts. 

"               "          per  passenger     11.82    "  2.71  "      3.82    " 

EXTRACTS  FROM  CENSUS  BULLETIN  OF  APRIL 
24,  1892. 

The  bulletin  was  prepared  by  Mr.  C.  H.  Cooley,  under 
the  supervision  of  Mr.  Henry  C.  Adams,  of  the  Inter- 
state Commerce  Commission,  and  covers  statistics  of  50 


118  STREET    RAILWAY    MOTORS. 

lines  of  street  railway,  10  operated  by  cable,  10  by  elec- 
tricity, and  30  by  animal  power.  The  total  cost  of  the 
10  cable  roads,  including  equipment,  is  given  as  $26,- 
351,416.  The  total  number  of  passengers  carried  was 
101,995,695,  at  a  total  cost  of  $3,286,461.  The  operating 
expenses  per  car-mile  were  14.13  cents,  and  the  operating 
expenses  per  passenger  carried  3.22  cents.  The  length 
of  all  tracks,  including  sidings,  was  nearly  143  miles. 

The  total  cost  of  the  10  electric  roads,  including  equip- 
ment, is  given  as  $2,426,285.  Total  track  mileage  of 
67.22  miles.  Passengers  carried,  8,031,214,  at  a  cost  of 
$326,961,  or  13.21  cents  per  car-mile  and  3.82  cents 
per  passenger. 

The  expenses  per  car-mile  on  cable  roads  varies  from 
9.39  cents  to  21.91  cents;  on  electric  roads  from  8.34 
cents  to  36.04  cents. 

The  density  of  passenger  traffic  is  about  six  times  as 
great  upon  the  cable  as  upon  the  electric  railways. 

The  editor  of  the  Street  Railway  Journal,  of  Chicago, 
gives,  from  his  own  figures  as  secretary  of  the  Chicago 
City  Railway  for  1890,  cost  of  operation  of  cable  cars, 
9.65  cents  per  car-mile. 

The  Philadelphia,  Record  gives,  for  three  months  on 
the  West  End  Railway,  of  Boston  : — 

Expenses  per  Car -Mile. 

April         .        Electric,  21.75  cts.         .        Horse,  24.54 
May  .  "       22.36    "  .  "      24.04 

June          .  "       20.37    "          .  "      23.52 

The  Earnings  were — 

April         .        Electric,  34.05  cts.         .        Horse,  31.77 
May  .  "       33.43    "  .  "     34.22 

June  "       42.71    "  "     36.85 


CABLE   AND    ELECTRIC   ROADS. 


119 


Charles  H.  Davis,  C.  E.,  in  a  printed  circular,  gives 
some  interesting  facts  and  figures  in  regard  to  electric 
roads : — 

Cost,  including  all  Plant  except  Real  Estate. 


A  road  of  2  miles  with.    8  cars  costs 


3 
4 
5 
6 
8 

10 
12 


10 
12 
15 
20 
25 
30 
40 


$70,000 
92,000 
110,000 
128,000 
165,000 
199,000 
248,000 
318,000 


Investment  and  Operating  Expenses  Compiled  from 
Edison  Co. 


Electric. 

Horse. 

Cable. 

Real  estate,  road,  and  equipments  per  mile  of  street 

$38,500 

$33,406 

$350,325 

track 

27,780 

31,093 

184,275 

Car-miles  per  annum  per  mile  of  street 

76,158 

43,345 

309,395 

Passengers  carried  per  annum  per  mile  of  street 

237,038 

251,816 

1,355,965 

"       per  car-mile  

3.10 

5.80 

4.38 

Operating  expenses  per  car-mile,  cents  

11.02 

24.32 

14.12 

Interest  at  6  per  cent,  on  investment  per  car-mile,  cts. 

3.03 

4.62 

6.97 

Total  interest  and  expenses  per  car-mile,  cents      .    . 

14.05 

28.94 

20.91 

Cost  per  passenger  carried,  interest  excluded    .    .    . 

3.55 

4.18 

3.22 

"      "           "               "             "        included    .    .    . 

4.53 

4.98 

4.77 

The  cost  of  power  on  horse  railroads  has  averaged  as 
follows  : — 


New  York  City 

Philadelphia 

Chicago 


8  to    9  cents  per  car-mile. 

9  to  10     "          "          " 
10  to  11      "          "          " 


120 


STREET    RAILWAY    MOTORS. 


CONDITIONS,  AS  PER  DAVIS  CIRCULAR. 
Day  of  18  Hours. 

Speed. — Electricity,  6|  miles  per  hour,  120  miles  per 
day.  Horses,  4  miles  per  hour,  72  miles  per  day. 

Depreciation. — Electricity  (of  power),  15  per  cent. 
Horses,  20  per  cent.  Car  repairs  :  Electricity  of  motors, 
20  per  cent. ;  of  cars,  10  per  cent.  Horse-cars,  5  per  cent. 

Repairs. — Track  and  line  repairs  :  Electricity,  15  per 
cent.  Horses,  10  per  cent. 

Service. — Three  men  per  car:  Electricity,  $1.87  each. 
Horse,  $1.60  each. 

Cost  of  Track  and  Line  per  Mile. — Electricity,  $10,000. 
Horse,  $5000. 

Value  of  Car. — Electricity,  $3000,  with  motor. 
Horse,  $1900,  with  6  horses.  Coal,  4  pounds  per  H.  P., 
$4  per  ton. 

Average  Operating  Expenses  of  22  Electric  Roads  per 
car -mile. 


Highest. 

Lowest. 

Average. 

Maintenance  of  road-bed  and  track  (cents) 

1.80 

0.10 

.54 

line 

.95 

.01 

.12 

power  plant 

.86 

.05 

.36 

Cost  of  power 

4.95 

.48 

1.96 

Repairs  on  cars  and  motors 

5.24 

.59 

1.80 

Transportation  expenses 

9.47 

2.74 

4.98 

General  expenses 

2.95 

.79 

1.26 

Total       

22.99 

7.80 

11.02 

Another  statement,  including  7  electric  roads,  gives 
an  average  for — 


Operating  expenses,  per  car-mile 
Cost  per  passenger  carried 


9.83  cents. 
3.28      " 


CABLE   AND    ELECTRIC    ROADS.  121 

ESTIMATES  OF  COST. 

The  comparative  estimates  of  cost  by  the  different 
systems  will  be  made,  as  previously  stated,  by  assuming 
similar  conditions  in  all  cases,  viz.  :  Length  of  road,  6 
miles;  of  single  track,  12  miles.  Cars  in  use  on  motor 
lines,  60 ;  reserve,  20  per  cent. ;  total,  75.  Horse  lines, 
90,  regular ;  112,  total.  Speed,  motor  lines,  6  miles  per 
hour  ;  horse,  4  miles.  Time,  16  hours  per  day.  Daily 
motor  mileage,  96  miles  each  ;  daily  motor  mileage 
total,  5760  miles.  Daily  car  mileage  of  horse-cars,  64 
miles  each  ;  daily  car  mileage  total,  5760.  Number  of 
horses  to  a  car,  8  ;  total  horses,  with  reserve,  900. 

On  many  roads  the  speed  is  greater  and  the  car  mile- 
age proportionately  increased ;  but  for  a  comparative 
estimate  these  figures  will  answer  as  well  as  others. 

Conductors,  engineers,  motormen,  and  gripmen  will 
be  allowed  $2  per  day ;  fireman  and  drivers,  $1.50. 

For  horse-stalls  it  will  be  proper  to  allow  stalls  5  by  9 
and  5  feet  to  middle  of  passage ;  total  per  horse,  70 
square  feet.  For  each  car,  250  square  feet,  to  allow  for 
passages  and  for  price  of  lots,  $1.50  per  square  foot. 
To  utilize  space,  cars  can  be  placed  on  the  ground  floor, 
and  horses  partly  on  first  and  partly  on  second  floor. 
The  space  required  for  cars  on  the  horse  line  will  be 
28,000  square  feet,  and  for  horses,  63,000  ;  in  addition 
to  this,  about  2000  square  feet  must  be  allowed  for 
offices,  making  a  total  of  93,000,  or  100,000  square  feet 
of  floor  space.  Of  this,  20,000  feet  of  first  floor  can  be 
used  for  stalls,  and  all  of  the  second  floor,  so  that  the 
whole  ground  area  will  be  50,000  square  feet. 


122  STREET  RAILWAY  MOTORS. 

HORSE  RAILROADS. 

Cost  of  Plant. 

Track,  1  mile  of  double  track,  laid  with 

65-pound  rail,  including  ties,  spikes,  etc.  $20,000 

Paving,  9282  sq.  yds.  granite  paving,  14  feet 
wide,  4  feet  between  track,  and  1^  feet  on 
each  side,  at  $3  per  square  yard 


Cost  of  one  mile       ...... 

Cost  of  six  miles      ...... 

Car-sJieds,  Stables,  and   Offices. 

Land,  50, 000  square  feet,  at  $1.50  .          .         $75,000 

Buildings,  offices,  car-sheds,  and  stables          .  80,000 


Total  for  land  and  buildings        .         .         .       $155,000 

Cars  and  Horses. 

900  horses,  with  harness,  wagons,  etc.,    $150  .       $135,000 
112  cars,  $1000 .         112,000 

$247,000 


Total  cost  of  plant  for  six  miles  .         .       $689,076 

Expenses  of  Operation. 

Feed  for  900  horses,  at  34  cents  per  day  .  .  $306.00 

Repairs  of  harness,  lT2ff  mills       "      "     .  .  J0.80 

Shoeing  horses,  6T8^  mills             "      "     .  .  56.70 

Stable  expenses,  1.15  cents          "      "     .  .  103.50 

Replacing  horses,  6T3o  mills         "      "     .  .  56.70 

$533.70 

Per  horse  per  day,  60  cents  ;  per  year,  $219. 
Per  car-mile  for  stable  expenses,  W&°»  9-26  cents. 


CABLE   AND    ELECTRIC   ROADS.  123 

OTHER  EXPENSES. 

The  other  expenses  of  operation  can  be  taken  from 
the  former  estimate  based  on  the  Second  Avenue  Rail- 
road data  by— 

Cars,  repairs,  conductors,    and  drivers,    per 

car-mile 8.00  cents. 

Track  repairs 1  68      " 

General  and  incidental  expenses     .          .         .  5.30      " 

14.98 
Add  expenses  of  power,  as  above    .         .         .         9.26      " 

Total  expense  of  horse-car  service  per  car-mile      24.24  cents. 

CABLE  ROADS. 
Notes  from  Fairohild  on  Street  Railways. 

The  average  horse-power  to  1000  feet  of  cable  is  4.6. 

The  power  to  move  cable  alone  is  from  35  to  75  per 
cent,  of  indicated  horse-power  of  engines  at  station. 

To  determine  approximately  the  amount  of  steam 
horse-power  required  for  a  line  less  than  10  miles  of 
rope,  allow  4-horse  power  to  each  1000  feet  of  rope,  each 
90°  bend  equal  to  1500  feet  straight,  with  addition  of 
3-horse  power  for  each  car  and  60  horse-power  for  ma- 
chinery. 

If  the  power  required  for  propulsion  of  cars  be  taken 
at  3  H.  P.  per  car,  on  line  including  reserve,  the  power 
required  for  75  cars  would  be  225  on  the  line;  and  as 
this  is  generally  estimated  at  40  per  cent,  of  the  steam 
horse-power  at  the  central  station,  60  per  cent,  being 
absorbed  by  friction  and  other  resistances  of  rope  and 
machinery,  the  power  to  be  provided  in  engines  and 


124  STREET    RAILWAY    MOTORS. 

boilers  would  be  562  H.  P.,  or,  in  round  figures,  600 
H.  P. 

If  the  second  rule  be  applied,  12  miles  of  cable  =  63360 
feet,  and  at  4  H.  P.  per  1000  feet  =  252  H.  P.  Allow 
4  right-angled  turns  in  the  6  miles;  thus  4  x  1500 
=  6000,  and  6  X  4  =24  H.  P.  to  be  added  for  turns. 

75  cars  at  3  H.  P.  per  car  «  225  H.  P.,  and  the  allow- 
ance of  60  H.  P.  for  machinery  makes  the  total  561  H. 
P.,  or  almost  the  same  as  before. 

For  electrical  lines  the  actual  percentage  of  the  steam- 
power  utilized  at  the  motor  car  is  said  to  be  from  30  to 
40  per  cent.,  so  that  the  loss  in  transmission  may  be  as- 
sumed as  the  same  as  in  cable  lines,  60  per  cent.,  and  the 
power  required  for  propulsion  is  also  nearly  the  same. 
This  will  make  the  steam-power  required  for  cable  and 
electric  lines  at  the  central  station  about  the  same. 

For  a  pneumatic  or  compressed  air  line,  running  75 
cars  at  intervals  of  2  minutes,  the  quantity  of  free  air 
required  per  minute  is  1800  cubic  feet,  and  the  horse- 
power required  about  550,  so  that  in  all  these  systems 
the  power  required  at  the  central  station  is  practically 
the  same  for  equal  work  on  the  track  ;  but  while  60  per 
cent,  of  the  power  on  cable  and  electric  lines  is  lost  in 
transmission,  on  the  compressed  air  line  the  power  lost 
in  compressing  the  air  is  fully  restored  in  reheating,  as 
has  been  shown,  and  there  is  no  loss  in  transmission ;  but 
it  requires  much  more  power  to  operate  a  motor  than  to 
move  a  given  weight  by  direct  application  of  the  power 
of  a  rope  through  a  grip.  This  equalizes  the  power  re- 
quired at  the  central  station. 

In  computing  the  cost  of  plant  and  of  operation  of 
cable  roads,  the  large  area  occupied  by  stables  will  be 
dispensed  with,  but  the  car-sheds  must  be  retained  and 


CABLE  AND  ELECTRIC  ROADS.         125 

a  separate  building  is  required  for  power-house.  The 
number  of  cars  being  75,  will  require  18,000  square  feet 
and  the  offices  2000  square  feet.  The  power-house  and 
plant  will  require  about  100  X  200  =  20,000  square  feet ; 
in  all,  40,000  square  feet. 

The  track,  so  far  as  rails  and  paving  are  concerned, 
will  be  the  same  as  estimated  for  horse  roads ;  but  the 
special  constructions  required  for  the  use  of  the  cable 
add  very  largely  to  the  expense. 

Power-house,  Car-house,  and  Machinery. 
Real  estate,  40,000  sq.  ft.  ground,  $1.50  .         .       $60,000 

Buildings 80,000 

Engines  and  boilers,  settings,  etc.,  600  H.  P.  30,000 

Driving  machinery  .....         40,000 

Foundation,  heaters,  pumps,  and  sundries        .         10,000 

Cost  for  6  miles  .         .         ,  $220,000 

Average  cost  for  one  mile  ....         36,666 

Estimate  for  Street  Construction  on  One  Mile  of  Double 

Track. 

Track  per  mile         .         .         .         ...         .  $20,000 

9282  square  yards  paving,  $3           ..       .         .  27,846 

6600  cubic  yards  track  excavation,  75  cts.      .  4,950 
2640  cast-iron  yokes,  350  Ibs.  =  2,755,000  Ibs., 

1£  cts.        .  .. 13,860 

293  carrying  sheaves,  $3.75           ...         •  1,100 
7040  yards,  50   Ibs.  per  yard,  steel  slot-rails, 

2£  cts.  per  ]b 8,800 

51333  Ibs.  manhole  covers  and  frames,  If        .  898 
3323  cubic  yards   Portland  cement  concrete, 

$8.50          .         .         .         .     -    .         .  28,333 

5280  feet  double-track  laying,  $1    .         .         .  5,280 

Sewer  connections            .         .         .         .         .  3,000 

10727  lineal  feet  steel- wire  cable,  at  33  cts.      .  3,576 

Cost  of  one  mile  double  track  .         .     $117,643 

Cost  of  six  miles  double  track          .         .       705,858 


126  STREET    RAILWAY    MOTORS. 

Special  Construction. 

Main  vault  at  engine-house  and  fixtures  .         $8,000 

Two  end  vaults  with  fixtures    ....  5,000 

Special  sheaves,  crossing  curves,  etc.,  curve      .         18,000 

Total  for  6  miles $31,000 

Rolling-stock. 
75    Combination    grip    and   pasjfenger    cars    at 

$2200  each $165,000 

Summary  of  Cost  of  6  Miles  of  Cable  Line,  Double  Track. 
Power-house,  real  estate,  and  buildings  .         .      $220,000 
General  street  construction       ....         705,000 
Special  street  construction        ....  31,000 

Rolling-stock 165,000 

Engineering,  legal,  and  miscellaneous      .         .          20,000 

$1,141,000 
Cost  of  plant,  one  mile  ....        190,166 

In  the  attempt  to  estimate  the  cost  of  operation  of  a 
cable  road  based  on  the  cost  of  one  of  shorter  length,  it 
does  not  seem  reasonable  to  assume  that  the  depreciation 
of  cable  will  be  simply  in  proportion  to  length,  but  in  a 
much  higher  ratio.  If  length  is  doubled,  the  strain  for 
any  given  length  will  also  be  doubled,  and  the  friction 
and  wear  should  be  at  least  quadrupled.  The  wear  of 
sheaves  and  pullies  will  also  be  increased  to  a  great  extent. 

It  would  seem  reasonable,  in  the  absence  of  positive 
data,  to  estimate  the  expenses  of  repairs  and  removals 
of  rope,  sheaves,  pulleys,  and  other  street  construction, 
including  grips,  as  fully  equal  to  the  cost  of  repairs  of 
motors  in  other  systems ;  and  if  this  be  conceded,  there 
will  be  a  close  approximation  to  identity  of  cost  of 
power  under  similar  conditions  of  the  systems  in  general 
use. 


ELECTEIC   LINES.  127 

Cost  of  Operation  of  6  Miles  of  Double-track  Cable 
Road,  per  Day  of  16  Hours. 

13|  Tons  of  coal  for  600  H.  P.,  $3          ...  $40.50 

Water  and  grease     ......  6.50 

Depreciation  of  rope          .....  140.00 

Depreciation  of  plant  and  rolling-stock             .  78.00 

120  Gripmeu  and  conductors,  $2     .         .         .         .  240.00 

Engineers  and  firemen      .         .         .         .         .  25.00 

Car-house  service,  cleaning,  inspecting,  etc.      .  20.00 

Power-house  expenses      .....  40.00 

Track  services 16.00 

Repairs  of  engines  and  machinery            .         .  26.00 

Repairs  of  cars,  trucks,  and  grips    .         ..         .  100.00 

Repairs  of  track  and  buildings          .         .         .  60.00 

Train,  shop,  and  miscellaneous  expenses           .  25.00 

Accidents 20.00 

Legal,  secret  service,  and  insurance         .         .  10.50 

General  and  miscellaneous        ....  50.00 

5760  car-miles,  cost $897.50 

Cost  per  car-mile,  $13.94  cents. 

This  estimate,  based  upon  prices  given  by  various 
authorities,  may  be,  in  some  items,  in  excess ;  but  as  the 
same  prices  will  be  retained  for  other  systems,  the  effect 
will  be  to  increase  slightly  the  daily  total  without  mate- 
rially affecting  the  comparative  estimates,  which  in  this 
investigation  are  of  most  importance. 


XII. 

ELECTRIC  LINES.      (FROM  VARIOUS  AUTHORITIES.) 

THE  cost  of  steam  power-house  plant  complete,  in- 
cluding building  and  smoke-stack,  is  rated,  for  high- 
speed and  non-condensing  engines,  at  from  $45  to  $60 


128  STREET    RAILWAY    MOTORS. 

per  horse-power ;  for  compound  engines,  from  $60  to  $75 ; 
and  for  electrical  equipments,  $35  to  $45  per  horse-power. 

The  usual  unit  of  horse-power  is  8  square  feet  of 
heating  surface,  evaporating  30  Ibs.  water  per  hour 
for  sectional  or  water-tube  boilers,  and  15  square  feet 
for  tubular. 

The  following  table  gives,  approximately,  the  horse- 
power at  axles  required  to  propel  a  16-foot  car,  weigh- 
ing, with  its  equipments  and  a  moderate  load  of  pas- 
sengers, 5  tons,  up  grades  of  from  1  to  10  per  cent.,  at 
the  uniform  rate  of  8  miles  per  hour.  On  ordinary 
street-car  tracks  the  traction  is  said  to  average  about  20 
Ibs.  per  ton,  but  is  sometimes  more,  and  the  commer- 
cial efficiency  of  the  motors  must  be  taken  at  60  per 
cent.  Thus,  for  a  level  track,  the  power  required  will  be 

-|  f\r\ 

5280  X8n-60x20x5^-  33,000  x  —  =  3.5  horse- 
power at  axles ;  and  for  grades,  as  follows,  from  1  to  10 
per  cent.: — 

0  =    3.5  H.  P.  6  =  22.5  H.  P. 


1  =  6.5 
2=  9.5 
3  =  13.0 
4=  16.0 
5  =  19.0 


7  =  25.5 

8  =  28.5 

9  ==  32.0 
10=35.0 


It  is  very  important,  in  the  management  of  an  elec- 
trical plant,  that  the  number  of  power  units  should  be 
such  that  the  disabling  of  one  of  them  will  not  interfere 
with  the  success  of  the  system,  and  the  same  remark  is 
also  applicable  to  other  systems. 

On  the  East  Cleveland  Electrical  Road,  70  motor  cars 
and  70  trailers  are  in  daily  use.  One  electrical  horse- 
power is  obtained  for  every  five  pounds  of  slack  or  four 


ELECTRIC   LINES.  129 

pounds  of  nut  coal.     Evaporation,  7J  pounds  of  water 
per  pound  of  slack. 

ELECTRIC  TRACTION  EFFICIENCY. 

Of  the  total  indicated  horse-power  developed  by 
ordinary  engines,  10  per  cent,  is  consumed  by  the  friction 
of  the  running  parts. 

The  loss  at  the  dynamo  is  from  10  to  15  per  cent., 
being  about  75  per  cent,  of  the  indicated  horse-power  as 
the  station  efficiency. 

The  line  efficiency  is  generally  about  90  per  cent. 

In  the  average  of  roads  now  in  operation,  the  propor- 
tion of  the  indicated  horse-power  of  the  engines  trans- 
mitted to  the  motor  for  propulsion  of  cars  is  between 
55  and  60  per  cent. 

The  average  efficiency  of  the  car  motors  themselves 
may  be  taken  at  75  per  cent.,  so  that  the  propulsion  of  the 
horse-power  of  engines  actually  applied  to  propulsion 
of  cars  is  60  X  75  per  cent.  =  45  per  cent.  In  a  ma- 
jority of  cases  it  is  stated  that  the  actual  commercial 
efficiency  does  not  rise  above  40  per  cent.  (Crosby 
&  Hall,  p.  228),  which  is  about  the  same  as  in  cable  lines. 

Cost  of  Items  entering  into  the  Construction  of  Electrical 
fiailroads  and  Equipments,  from  Various  Sources  of 
Information. 

Single-track  railroad,  average  per  mile       .         .     $10,000 
No.  0  copper  wire  to  make  track  a  good  conduc- 
tor, per  mile   .         .         .         ....         .  400 

Labor  in  laying  wire  and  binding  to  rail,  per  mile  200 

Wooden  poles,  90  to  the  mile,  placed,  per  mile    .  600 

Iron  poles,  90  to  the  mile,  placed,  per  mile         .  2,500 

Trolley  wire,  span  wires,  and  insulators,  per  mile  700 

Feed  wire  in  place,  per  mile        ....  1,000 

9 


130  STREET    RAILWAY    MOTORS. 

1  mile  single  track,  with  wooden  poles        .         .     $13,000 

1         "          "          "          wire  poles    .         .         .  15,000 
Car  bodies,  ready  for  motors,  750  to  1500  dollars, 

average  each   .......  1,000 

Long  bodies,  $1250  to  $2000,  each  average           .  1,625 

Trucks  for  long  cars    ......  600 

Two  15-horse  motors,  from  1800  to  2500  dollars. 
If  one  motor  is  used,  from  1100  to  1800  dollars. 
Car  ready  to  operate  (electrical  equipment,  $2250)  3,500 
For  station  power-plant  complete,  allow  per  horse- 
power     ........  50 

For  station  electrical  plant          ....  40 

For  both  plants 90 

Investment  in  station  machinery,  per  car  operated      1,350 

Keal  estate  may  be  generally  covered  by  $50  per  H.  P. 
of  station,  or  by  $750  per  car  operated,  but  is  extremely 
variable. 

Average  of  22  electric  lines  gives  cost  of  power,  as 
reported,  2.32  cents  per  car-mile ;  but  published  reports 
are  usually  unreliable. 

Cents. 
Maintenance  of  line  is  covered  by  5  per  cent,  of 

cost,  say  per  car-mile       .....  0.4 
Maintenance  of  track  is  covered  by,  per  car-mile  1.08 
Maintenance  of  car  bodies  and  trucks,  per  car- 
mile         0.72 

Conductors  and  motor  men          .         .         .         .  4.50 

Summary  of  Expenses  as  given  by  Crosby  &  Hall, 
page  320  of  Electric  Railway. 

Cents. 

Power  delivered  on  line  per  car-mile  .  .  .  1.35 
Repairs  011  electric  machinery  of  car  .  .  .  1.00 

Repairs  on  line 0.43 

Conductors  and  motor  men  .  .  .  .  .4.50 
Repair  on  cars  and  track  .  .  .  .  .0.72 
Maintenance  of  roadway  .....  1.08 

General  expense 2.00 

Accidents 0.25 

11.33 


ELECTRIC   LINES.  131 

The  cost  of  a  trail  car  would  be  covered  by  5  to  6 
cents  per  mile.  The  expenses  of  the  West  End  Rail- 
way of  Boston  for  an  average  of  5  months  were  per  car- 
mile  operated  by  electricity : — 

Cents. 
Motor  power  .......       7.44 

Car  repairs 1.33 

Damages 0.43 

Conductors  and  drivers  .....       7.14 

Other  expenses     s         .         .         .         .         .         .4.78 

Total  expenses 21.12 

From  which  it  appears  that  the  actual  cost  on  the 
West  End  Railway  was  nearly  twice  as  great  as  the  sup- 
posed average  estimate  above  given  by  Crosby  &  Hall. 

An  estimate  will  now  be  made  of  the  cost  per  car- 
mile  of  electrical  railway  service  based  on  the  conditions 
stated,  viz  : — 

Line  6  miles  double  track,  service  two-minute  inter- 
vals, cars  60,  reserve  15,  horse-power  at  station  600, 
daily  mileage  5760  miles. 

Power-house,  Car-house,  and  Machinery. 

Real  estate,  40,000  sq.  ft.  ground  at  $1.50           .  $60,000 

Buildings 80,000 

Engines,  boilers,  settings,  etc.,  for  600  H.  P.      .  30,000 

Station  machinery 25,000 

Foundations,  heaters,  pumps,  and  sundries        .  10,000 


Cost  for  6  miles $205,000 

Proportion  for  one  mile         ....       34,166 


132  STREET    RAILWAY    MOTORS. 

Estimate  of  Street  Construction  for  One  Mile  of 
Double  Track. 

Track,  one  mile $20,000 

9282  square  yds.  paving,  $3        .          .          .          .  27,846 

Track  wire  laid 1,200 

180  iron  poles 5,000 

Trolley  wires,  span  wires,  and  insulators  .         .  1,400 

Feed  wires  in  place    ......  2,000 


Total  street  construction      ....     $57,446 
Cost  for  6  miles $344,676 

Equipment. 
75  car  bodies,  trucks,  and  motors,  $3500     .         .  $262,500 

Summary  for  6  Miles. 

Power-house  and  plant $205,000 

Street  construction 344,676 

Equipment 262,500 

Auxiliary  appliances 15,000 

Special  construction    ......         5,000 

Engineering,  legal,  and  miscellaneous         .          .       20,000 

Total  cost  for  6  miles $852,176 

Cost  of  Operation  of  Six  Miles  Double-track  Electric 
Line  per  Day  of  16  Hours. 

13£  tons  of  coal  for  600  H.  P.,  $3    .         .         .  $40.50 

Water,  oil,  and  grease     .....  6.50 

Depreciation  of  plant  and  rolling-stock  .         .  78.00 

120  motor  men  and  conductors,  $2          .         .  240.00 

Engineers,  firemen,  and  dynamo  tenders         .  35.00 

Car-house  service,  cleaning,  inspecting,  etc.     .  30.00 

Power  and  car-house  expenses       .         .         .  12.00 

Track  service 16.00 

Repairs,    engines,    working   of    line,    miscel- 
laneous       .......  26.00 

Repairs  of  cars,  trucks,  and  motors         .          .  140.00 


ELECTRIC   LINES.  133 

Repairs     of    track,     overhead     construction, 

buildings $80.00 

Track  cleaning,  train,  and  shop  expenses       .  25.00 

Accidents 20.00 

Legal,  secret  service,  insurance      .         .         .  10.00 

General  and  miscellaneous      ....  50.00 


5760  miles $809.00 

Cost  per  car  mile,  14.04  cents. 

It  appears  that  with  equal  length  of  road  and  equal 
car  mileage  the  cost  of  operation  of  cable  and  electric 
lines  is  nearly  the  same  on  both.  The  depreciation  of 
cable  is  about  offset  by  the  repairs  of  overhead  wires, 
and  dynamo  tenders,  other  items  the  same. 

GENERAL  SUMMARY. 

Cost  of  Plant  and  of  Operation,  for  Six  Miles  of  Double 
Track  Operated  by  Horse-power — 2-minute  Intervals. 

Land $75,000 

Buildings 80,000      . 

Track  and  paving  ......  287,076 

Horses 135,000 

Cars 112,000 

Cost  of  plant $689,076 

Interest  at  6  per  cent.      .....  41,345 

Car-miles  per  annum       .         .         .         .         .  2,102,400 

Interest  per  car-mile        .....  2  cents. 

Cost  of  operation,  without  interest ...  24  cents. 

Cost  of  operation,  with  interest  on  plant          .  26  cents. 

Cost  of  horse-power,  not  including  drivers       .  9  cents. 


134  STREET    RAILWAY    MOTORS. 

Cost  of  Plant  and  of  Operation  of  Six  Miles  of  Double 
Track  Operated  by  Steam  Motors — 2-minute  Intervals. 

Land $60,000 

Buildings  and  machinery  of  shops         .         .  100,000 

Track  and  paving 287.076 

Rolling-stock 300,000 

Miscellaneous 20,000 


Cost  of  plant $767,076 

Interest  at  6  per  cent 46,025 

Car-miles  per  annum   .....     2,102,400 
Interest  per  car-mile    .....  2.09  cents. 

Cost  of  operation,  without  interest,  per  car-mile  21.22  cents. 

Cost  of  operation,  with  interest,  on  plant  per 

car-mile          ......         23.31  cents. 

Cost  of  steam-power  alone,  without  engineer  or 

fireman  per  car-mile     .....  9.50  cents. 

Cost  of  fuel  alone     .         .         .         .         .         .  2.65  cents. 

Cost  of  Plant  and  of  Operation  of  6  Miles  of  Double  Track 
Operated  by  the  Ammonia  Motor — Intervals  between 
Cars,  two  Minuter. 

Although  the  data  furnished  by  the  actual  operations 
at  New  Orleans  do  not  exhibit  any  economy  as  compared 
with  steam,  yet  when  it  is  considered  that  the  principal 
work  in  generating  power  is  done  in  a  stationary  instead 
of  a  locomotive  boiler,  in  which  fuel  can  be  used  at  half 
price,  with  at  least  50  per  cent,  more  evaporation,  it  is 
reasonable  to  assume  that  in  a  properly  constructed  and 
operated  plant  there  should  be  a  saving,  as  compared 
with  steam  motors,  of  at  least  $75  per  day  in  fuel.  If 
separate  motors  are  used,  there  will  be  no  reduction  in 
the  cost  of  plant ;  but  if  the  motors  and  cars  are  com- 
bined, less  ground  will  be  required,  making  a  saving  of 
$18,000. 


ELECTRIC   LINES.  135 

Assuming  minimum  expenditures,  the  estimate  will 
be:— 

Land,  22,000  sq.  ft.,  $1.50      ....  $33,000 

Building  and  apparatus           .  80,000 

Track  and  paving 287,076 

Rolling-stock,  75  cars  and  motors,  $3500         .  262,500 

Miscellaneous 20,000 

Cost  of  plant $682,576 

Interest  at  6  per  cent.  ....  40,954 

Car-miles  per  annum 2,102,400   > 

Interest  per  car-mile       .....     1.95  cents. 

Cost  of  operation  per  car-mile,  without  interest  19.92  cents. 
Cost  of  operation,  with  interest  on  plant        .  21.87  cents. 
Cost  of  power  alone,  without  engineer  or  fire- 
man .......     8.20  cents. 

Cost  of  fuel  alone 1.30  cents. 

HOT-WATER  MOTOR. 

No  separate  estimate  is  required.  The  cost  in  every 
particular  may  be  taken  as  the  same  as  steam,  both  as 
regards  plant  and  operation.  Any  slight  saving  by  the 
first  charge  of  hot  water  is  fully  offset  by  disadvantages 
and  expenses  in  pumping  back  the  water  for  reheating 
on  return-trip.  If  not  pumped  back,  the  loss  will  be 
still  greater. 

Cost  of  Plant  and  Operation  of  6  Miles  of  Double  Track 
Operated  by  Gas  Motors — 2-minute  Intervals. 

As  it  is  proposed  in  cities  to  use  independent  motors, 
the  cost  of  plant  will  be  taken  as  the  same  as  steam,  with 
a  deduction  of  $500  each  in  the  cost  of  motors,  making 
them  $2500.  The  fuel  for  motor  and  car  will  be  taken 
at  1^  cents  per  mile  run  for  the  train.  No  fireman  re- 
quired. 


336  STREET   RAILWAY    MOTORS. 

Estimate. 

Land $60,000 

Building  and  shop  machinery       .         .         .  100,000 

Track  and  paving 287,076 

Rolling  stock         . 262,500 

Miscellaneous        ......  20  000 

Cost  of  plant          ...... 

Interest  at  6  per  cent.  .... 

Car  miles  per  annum              ....  2,102,400 

Interest  per  car  mile               ....  2.08  cents. 

Cost  of  operation  per  car-mile,  without  interest  17.62  cents. 

Cost  of  operation  per  car-mile,  with  interest    .  19.70  cents. 
Cost  of  power  alone,  without  motor  man,  per 

car-mile     .                  7.30  cents. 

Cost  of  fuel  alone  per  car-mile      .         .         .  1.30  cents. 

'Cost  of  Plant  and  of  Operation  of  6  Miles  of  Doable 
Track  Operated  by  Compressed  Air  Motors— Z-minute 
Intervals. 

Land $33,000 

Buildings  and  machinery,  for  repairs   .         .  80,000 

Engines,  boilers,  setting        ....  30,000 

Pipes  and  reservoir       .....  5,000 

Track  and  paving          .....  287  076 

Rolling-stock 262,500 

Miscellaneous        .         .         .         .         .         .  20,000 

Cost  of  plant        ......  $717,576 

Interest  at  6  per  cent 43,055 

Car  mileage  per  annum         ....  2,102,400 

Interest  per  car-mile 2.05  cents. 

Cost  of  operation  per  car-mile,  without  inte- 
rest on  plant 13.16  cents. 

Cost  of  operation  per  car-mile,  inclusive  of 

interest  on  plant 15.21  cents. 

Cost  of  power  alone  per  car-mile,  including 

repairs 4.10  cents. 

Cost  of  fuel  alone  per  car-mile     ...  7  mills. 


ELECTRIC   LINES.  137 

Cost  of  Plant  and  of  Operation  of  6  Miles  of  Double 

Track  Operated  by  Cable — %-minute  Intervals 

Land     ....        V  ">*.         .         .  $60,000 

Buildings .  80,000 

Engines,  boilers,  setting,  and  machinery      .  80,000 

Track  and  paving 287,076 

Rolling-stock 165,000 

Street  construction 448,924 

Miscellaneous 20,000 

Cost  of  plant $1,141,000 

Interest  at  6  per  cent 68,460 

Car-miles  per  annum 2,102,400 

Interest  per  car-mile     .....  3.25  cents. 
Cost  of  operation  per  car-mile,  without  inte- 
rest              13.94  cents. 

Cost  of  operation  per  car-mile,  with  interest  17.19  cents. 

Cost  of  power  alone  per  car-mile           .         .  5.85  cents. 

Cost  of  fuel  alone  per  car-mile     ...  7  mills. 

Cost  of  Plant  and  of  Operation  of  6  Miles  of  Double 
Track  Operated  by  Electric  Lines — %-minute  Inter- 
vals. 

Land    .         .         .*"     " $60,000 

Buildings      .         .         .         .         .        ...  80,000 

Engines,  boilers,  setting,  and  machinery      .  65,000 

Track  and  paving 287,076 

Trolley  wires,  connections,  etc.,  in  street      .  56,600 

Rolling-stock         / 262,500 

Miscellaneous                 «         .         .         .         .  20,000 

Cost  of  plant          .         .         .         .-.'.'       $831,176 

Interest  at  6  per  cent 49,870 

Car-miles  per  annum    .                   .         .         .  2,102.400 

Interest  per  car-mile 2.37  cents. 

Cost  of  operation  per  car-mile,  without  inte- 
rest    14.04  cents. 

Cost  of  operation  per  car-mile,  with  interest  16.41  cents. 

Cost  of  power  alone  per  car-mile  .         .          .  4.25  cents. 

Cost  of  fuel  alone  per  car-mile      ...  7  mills. 


138  STREET    RAILWAY    MOTORS. 


XIII. 

LOW-PRESSURE  AIR  MOTORS. 

A  METHOD  of  propelling  street  cars  by  the  use  of 
compressed  air,  at  a  low  pressure  of  100  Ibs.  per  square 
inch,  was  proposed  in  San  Francisco.  The  car  reser- 
voirs were  to  be  of  about  50  cubic  feet  capacity  and  placed 
overhead  or  under  the  seats,  where  they  would  be  out  of 
the  way  and  would  not  interfere  with  the  seating  capa- 
city. An  underground  pipe  was  to  be  carried  between 
the  tracks,  the  diameter  of  pipe  4  to  6  inches,  and  at 
intervals  of  500  feet  a  nozzle  was  to  be  provided,  to 
which  attachment  could  be  made  to  renew  the  supply  of 
air  in  the  reservoirs  when  necessary. 

This  system  seems  to  have  been  proposed  to  remedy  a 
purely  imaginary  difficulty.  It  was  assumed  that  there 
was  great  loss  of  power  and  great  expense  in  compressing 
air  to  high  tension  and  that  great  economy  would  result 
from  the  use  of  lower  pressure.  It  has  been  shown  that 
the  cost  of  fuel  in  compressing  air  to  500  pounds  is  only 
7  mills  per  car-mile,  which  constitutes  but  about  5  per 
cent,  of  the  whole  expense  of  operation  •  and  even  if 
some  economy  should  result  from  lower  compression, 
which  is  doubtful,  it  would  not  compensate  for  the  very 
serious  objection  of  frequent  stoppage  to  replenish  the 
supply. 

In  the  pamphlet  which  advocates  the  merits  of  the 
low-pressure  system,  objections  to  the  high-pressure  are 
stated ;  but  there  are  none  that  have  not  been  fully  con- 


LOW-PRESSURE   AIR   MOTORS.  139 

sidered  and  answered.  There  is,  however,  an  objection 
to  the  cable  urged  by  the  writer  that  has  much  force,  and 
that  is,  that  the  power  of  the  cable  must  be  sufficient  for 
the  maximum  business  at  the  most  busy  hours  of  the 
day,  and  that  this  same  power  must  be  expended  when 
the  travel  is  a  minimum,  if  there  is  only  a  single  car 
upon  the  line.  To  avoid  this  great  waste  of  power  it  is 
stated  that  some  cable  lines  have  stopped  the  machinery 
at  night  and  substituted  horse-power.  Cables  are  eco- 
nomical only  with  a  very  large  volume  of  business,  and 
similar  objections,  although  not  to  so  great  an  extent, 
apply  to  electric  lines.  A  current  must  traverse  the 
whole  line  or  section  of  line  wire  for  a  single  car. 
There  is  always  a  serious  loss  in  the  transmission  of 
power  to  long  distances  from  the  generating  plant,  and 
for  this  reason,  as  for  others  named,  independent  motors 
which  carry  their  own  power  are  far  preferable. 

CARBONIC  ACID  MOTOR. 

The  New  York  World,  of  July,  1892,  contained  a 
long  article  presenting  the  claims  of  a  new  motor  to  be 
operated  by  carbon  dioxide,  usually  called  carbonic  acid. 
It  was  claimed  that  10  horse-power  could  be  obtained 
from  6T7Q-  pounds  of  the  gas,  at  a  cost  of  20  cents  for  24 
hours ;  that  pressures  of  from  1000  to  5000  pounds  per 
square  inch  could  be  produced,  and  that  this  "  wonderful 
motive  fluid"  was  to  be  used  even  for  road  vehicles 
and  for  agricultural  purposes. 

The  absurdity  of  such  claims  is  self-evident.  Car- 
bonic acid  condenses  into  a  liquid  at  570  pounds  per 
square  inch,  and  there  can  be  no  further  condensation. 


140  STREET    RAILWAY    MOTORS. 

It  is  impossible  to  secure  more  power  from  the  expan- 
sion of  a  gas  than  was  expended  in  its  compression  ;  and 
even  if  a  pressure  of  5000  pounds  were  attainable,  it 
could  not  be  utilized,  as  was  shown  in  the  Beaumont 
tests,  until  reduced  to  a  working  pressure  of  about  200 
pounds.  Further  comment  is  unnecessary. 


XIV. 

STORAGE   BATTERIES. 

No  estimates  have  been  made  upon  a  line  operated 
by  the  use  of  storage  batteries,  for  the  reason  that  no 
data  are  at  present  available.  Up  to  the  present  time 
it  is  understood  that  the  cost  exceeds  that  of  the  cable 
and  trolley  lines;  but  it  is  claimed  that  greater  economy 
has  already  been  secured  than  by  the  use  of  horse-power, 
and  that  improvements  are  constantly  reducing  the  ex- 
pense. It  may  be  that  there  is  a  future  to  the  storage 
battery  that  will  in  time  enable  it  to  supplant  the  trolley, 
which  would  be  a  most  devoutly  to-be-wished-for  con- 
summation. The  trolley  is  not  only  unsightly  by  its 
poles  and  overhead  wires,  and  annoying  by  its  loud 
humming  noise,  but  it  has  proved  destructive  to  life  by 
contact  with  live  wires ;  and  the  obstruction  to  the  free 
use  of  the  fire  apparatus  by  overhead  wires  has  caused 
losses  greater  than  the  cost  of  the  lines  themselves,  of 
which  a  recent  fire  in  Boston  is  an  illustration,  if  the 
newspaper  accounts  can  be  relied  upon.  In  addition  to 
this,  lines  are  liable  to  be  deranged  by  electrical  storms 
in  summer  and  in  winter  by  snow  and  ice  on  rails  and 


STORAGE    BATTERIES.  141 

feed  wires,  which  break  the  electrical  connections.  The 
latter  evil  might  not  be  entirely  remedied  by  the  storage 
battery,  but  it  would  give  an  independent  motor  and 
avoid  blockades  all  along  the  line  from  any  trouble  at 
the  power-house. 

The  position  will  probably  not  be  controverted  that 
the  motor  and  system  of  transportation  that  commends 
itself  most  highly  to  the  approval  of  the  public  and  of 
capitalists  is  the  one  which  best  fulfils  the  following 
conditions  : — 

1.  Minimum  cost  of  plant. 

2.  Minimum  cost  of  operation,  including   interest   on 

plant. 

3.  Independent  motors  not  liable  to  stoppage  in  transit 

by  derangement  of  station  machinery. 

4.  Minimum  disturbance  of  streets,  pipes,  and  sewers. 

5.  Avoidance  of  unsightly  structures,  danger  from  shocks, 

or  impediments  to  the  free  use  of  fire  apparatus. 

6.  Surplus  power  in  motor  for  attachment  of  trail  cars 

at  hours  when  increased  capacity  is  demanded. 

7.  Freedom   from    liability   to   delay   in   transit   from 

storms,  ice,  or  sleet. 

The  several  systems  will  be  compared  with  reference 
to  the  above  conditions. 

Comparing  the  different  systems  that  have  been  under 
consideration,  by  including  in  the  operating  expenses  per 
car-mile  the  interest  on  the  cost  of  plant,  which  is  obvi- 
ously the  only  true  basis  of  comparison,  the  following 
results  are  presented  in  the  order  of  relative  economy. 
The  first  column  gives  the  cost  of  operation  per  car-mile, 
including  interest  on  plant ;  the  second  the  cost  of  power 


142  STREET   RAILWAY   MOTORS. 

per  car-mile,  and  the  third  the  cost  of  fuel  alone  per  car- 
mile  in  cents : — 

Comparison  of  Motors. 

Cents.  Cents.  Cents. 

Compressed  air  motors  .  15.21  4.10  0.7 

Electric   trolley   lines  .  16.41  4.25  0.7 

Cable  lines         .         .  .  17.19  5.85  0.7 

Gas  motors         .         .  .  19.70  7.30  1.30 

Ammonia  motors        .  .  21.87  8.20  1.30 

Steam  motors    .         .  .  23.31  9.50  2.65 

Hot-water  motors        .  .  23.31  9.50  2.65 

Horse-power      .         .  .  26.00  9.00  0.00 

The  relative  economy  in  regard  to  cost  of  plant  is  as 
follows  : — 

1.  Ammonia  motor $682,576 

2.  Horse-power 689,076 

3.  Compressed  air 717,576 

4.  Gas  motor .  729,576 

5.  Steam  and  hot-water  motors     .         .         .  767,076 

6.  Electric  lines 831,176 

7.  Cable  lines 1,141,000 

Ammonia  being  the  lowest  in  cost  of  plant,  the  other 
systems  increase  in  the  following  percentages :  Horse- 
power, 1  per  cent. ;  compressed  air,  5  per  cent. ;  gas,  7 
per  cent. ;  steam  or  hot  water,  12T3^  per  cent. ;  electric, 
18  per  cent.  ;  cable,  40  per  cent. 

Ammonia  Motor. — This  system  is  independent,  requires 
no  overhead  obstructions  or  disturbance  of  streets,  carries 
its  own  power,  and  is  not  liable  to  interruption  from 
trouble  at  the  central  station.  It  ranks  fifth  in  economy 
of  operation.  There  seem  to  be  difficulties  connected 
with  its  use,  as  it  was  abandoned  after  a  short  period  of 


STORAGE    BATTERIES.  143 

use  in  New  Orleans  in  favor  of  the  hot-water  motor  as 
being  "cheaper  and  less  troublesome" 

Horse-power. — Horse-power  needs  no  explanation.  It 
is  independent  and  generally  reliable,  but  too  slow  for 
any  approach  to  rapid  transit.  It  requires  no  special 
construction  in  and  causes  no  obstruction  to  streets,  but 
in  economy  of  operation  it  is  at  the  foot  of  the  list.  It 
also  creates  nuisances  by  requiring  stables  and  causing 
deposits  in  streets  which,  when  dry,  are  blown  into 
houses. 

Compressed  Air. — Compressed  air  seems  to  fulfil  every 
condition  as  a  perfect  motive  power.  It  stands  at  the 
head  of  the  list  in  economy.  In  cost  of  plant  it  is  only  5 
per  cent,  above  the  minimum,  but  in  cost  of  operation  it 
is  8  per  cent,  below  the  next  on  the  list.  These  motors  are 
independent,  there  can  be  no  losses  by  radiation  or  con- 
densation. The  charge  of  motors  can  remain  for  hours 
until  used.  The  plant  should  always  consist  of  a  number 
of  units,  and  the  derangement  of  one  will  not  affect  the  rest 
or  disturb  the  operation  of  the  line.  If  considered  desir- 
able, air  can  be  transmitted,  without  sensible  loss,  to  dis- 
tant points  to  reinforce  motors,  if,  from  any  cause,  such 
supplies  should  become  necessary.  The  speed  is  unlimited, 
except  by  municipal  regulations.  The  track  is  a  surface 
line  requiring  no  disturbance  of  streets  except  to  lay  the 
track.  There  is  no  possibility  of  explosions,  as  with 
steam  ;  no  shocks,  as  with  electricity  ;  no  stoppage  by 
break  of  circuit  from  ice  on  rail  or  wires  ;  no  collisions 
from  inability  to  detach  grip,  as  in  cable  lines  ;  and  no 
occupation  of  valuable  space  by  motor  machinery,  as  all 
such  machinery  is  under  the  floor  of  the  car  or  beneath 
the  seats,  and  entirely  out  of  view  ;  no  skilled  engineer 


144  STREET   RAILWAY    MOTORS. 

is  required,  as  an  ordinary  car  driver  can  learn  to  ma- 
nipulate the  lever  in  a  single  trip. 

The  motor  can  have  any  amount  of  surplus  power  to 
allow  one  or  more  trail  cars  to  be  attached  under  one 
conductor,  when  business  is  at  a  maximum,  and  thus 
secure  public  accommodation  at  a  minimum  of  expense ; 
and  the  ability  to  use  increased  power  when  needed  does 
not  cause  a  waste  at  other  times,  as  no  more  air  can  be 
used  at  any  time  than  is  required  for  propulsion,  and  in 
running  down  grade  the  motor  cylinders  act  as  brakes 
and  also  as  pumps  to  pump  back  air  into  the  reservoirs. 

It  will  thus  be  seen  that  there  is  not  one  of  the  con- 
ditions enumerated  as  desirable  in  a  perfect  motor  that 
this  does  not  fulfil ;  and,  on  the  other  hand,  it  is  not 
known  that  a  valid  objection  has  ever  been  found,  or,  in 
fact,  any  objection,  that  has  not  originated  in  the  igno- 
rance of  the  maker. 

The  system  is  not  only  adapted  to  surface  roads,  but 
is  also  the  best  possible  for  elevated  and  underground 
roads.  An  explanation  has  been  given  of  the  causes 
which  prevented  its  introduction  after  the  satisfactory 
test  of  1879  and  1880. 

Gas  Motors. — The  Connelly  Gas  Motor,  which  is  the 
only  gas  motor  known  to  the  writer,  has  been  in  process 
of  development  for  six  years,  and  seems  to  be  a  triumph 
of  mechanical  skill,  combining  strength  with  simplicity 
and  compactness.  It  promises  to  be  successful,  but  has 
not  as  yet  the  test  of  actual  experience  to  inspire  confi- 
dence. 

This  is  an  independent  motor,  free  from  all  the  defects 
of  the  horse,  cable,  and  electric  systems,  and  very  eco- 
nomical in  cost  of  fuel,  although  in  several  of  the  sys- 


STORAGE    BATTERIES.  145 

terns  fuel  forms  a  very  inconsiderable  portion  of  the 
total  expense. 

Steam  and  Hot  Water. — These  motors  are  classed 
together  as  equivalents.  They  are  independent  motors 
not  liable  to  stoppage  from  derangement  of  any  central 
plant ;  require  no  special  construction  or  changes  in  sur- 
face roads.  The  disadvantages  are  that  they  must  carry 
a  supply  of  fuel,  require  a  fireman  and  engineer,  must 
use  separate  motors,  are  liable  to  accidents  from  explo- 
sions, and  are  objectionable  from  exhaust  steam  with  its 
noise,  and  from  smoke,  cinders,  ashes,  and  coals.  In 
economy  it  stands  fifth  on  the  list,  horse-power  alone 
being  more  expensive.  It  is  true  that  these  motors  may 
be  run  without  firemen  ;  but  if  the  engineer  is  required 
to  attend  to  firing,  accidents  and  collisions  may  occur 
while  his  attention  is  diverted  from  the  lookout,  especi- 
ally in  crowded  thoroughfares. 

Electric  Lines  require  ground  connection  below  the 
rails  and  posts  and  trolley  wires  overhead.  The  motors 
are  not  independent,  but  must  receive  power  from  the 
central  station,  and  are  liable  to  be  burned  out  by  elec- 
tric storms  in  summer  or  impeded  by  break  of  circuit 
from  ice  on  track  or  feed  wires  in  winter.  Perhaps  the 
most  serious  objection  arises  from  the  impediment  to  the 
free  use  of  apparatus  for  extinguishment  in  case  of  fires, 
and  the  obstructive  and  unsightly  appearance  of  poles 
and  trolley  wires.  Electric  lines  stand  second  to  com- 
pressed air  in  cost  of  operation,  and  sixth  in  cost  of 
plant. 

Cable  Lines  have  the  same  disadvantage  as  the  elec- 
tric in  being  entirely  dependent  upon  the  central  plant 
for  the  power  of  propulsion.     Any  stoppage  there,  or 
10 


146  STREET    RAILWAY    MOTORS. 

break  of  cable,  stops  every  car  on  the  line,  and  repairs 
are  difficult  and  cause  very  serious  delays.  A  broken 
strand  has  sometimes  prevented  the  detachment  of  the 
grip  and  caused  most  serious  accidents,  one  of  which 
occurred  recently  in  Chicago.  The  plant  is  much  more 
expensive  than  in  any  other  system,  but  in  economy  of 
operation  its  place  is  third.  Many  of  the  reports  show 
greater  economy  of  operation  for  cable  than  for  trolley 
lines;  but  cable  lines  are  generally  metropolitan,  and 
have  a  much  larger  patronage  than  the  electric ;  under 
similar  conditions  the  superior  economy  disappears.  For 
a  light  traffic  the  cable  is  not  adapted. 

In  this  review  of  the  various  street  railway  systems 
it  has  been  the  aim  of  the  writer  to  state  facts,  so  far  as 
he  has  been  able  to  procure  them  from  the  sources  of 
information  within  his  reach,  and  to  make  comparisons 
without  bias.  If  he  has  appeared  to  lean  favorably 
towards  compressed  air,  it  has  been  from  a  conviction  of 
its  superior  merit,  and  from  the  fact  that  he  was  called 
upon  professionally  to  devote  much  time  and  attention 
to  the  investigation  of  this  subject,  and  therefore  claims 
the  right  to  give  opinions  with  confidence.  He  is  aware 
that  there  is  a  very  general  impression  that  compressed 
air  has  been  tried  and  has  been  found  wanting.  This 
is  a  grave  error ;  it  has  been  tried  and  proved  a  great 
success.  That  it  has  not  been  generally  used  is  the 
result  of  causes  that  have  been  here  explained  having 
no  relation  to  its  results.  It  is  now  in  successful  use  in 
France,  and  has  been  for  many  years,  although  in 
mechanical  construction  the  Mekarski  motor  is  inferior 
to  those  constructed  in  New  York  and  tested  on  the 
Second  Avenue  horse  and  elevated  roads  in  1879  and 


COST  OF  CARBONIC  ACID  AS  A  MOTIVE  POWER.      147 

1880,  and  the  plans  upon  which  these  motors  were  con- 
structed have  been  much  improved  upon  by  the  inventor 
since  that  date. 


XV. 

COST  OF  CARBONIC  ACID  AS  A  MOTIVE  POWER. 

THAT  carbonic  acid  is  entirely  too  expensive  to  be 
used  as  a  motive  power  can  be  readily  demonstrated. 

It  was  stated  in  the  article  from  the  New  York  World, 
referred  to  on  page  139,  that  the  cost  of  the  gas  is  never 
more  than  three  cents  per  pound,  and  the  following 
figures  are  given,  viz. : — 

98  Ibs.  sulphuric  acid,  at  $8  per  ton       .         .     .15  cents. 
100  Ibs.  limestone,  at  $3  per  ton      .         .         .     .784 
Labor  and  compressing   .....     .30 

$1.24 

Producing  44  pounds  of  gas,  at  a  total  cost  of  $1.24, 
which  is  2.8  cents  per  pound. 

These  figures  are  not  far  from  the  truth,  but  the 
power  of  the  carbonic  acid  when  produced  is  greatly 
overestimated. 

Using  the  exact  chemical  equivalents,  99.75  pounds 
of  pure  carbonate  of  lime  unite  with  97.82  pounds  of 
pure  sulphuric  acid  and  liberate  43.89  pounds  of  car- 
bonic acid. 

Sulphuric  acid  is  generally  sold  at  one  cent  per  pound, 
but  in  large  quantities  it  may  be  less,  and  the  assertion 
that  it  can  be  purchased  by  the  ton  at  $8  will  be 
assumed,  for  the  purposes  of  this  estimate,  as  correct, 


148  STREET   RAILWAY   MOTORS. 

making  the  cost  of  carbonic  acid,  as  stated,  2.8  cents  per 
pound. 

The  density  of  this  gas  at  atmospheric  pressure  is 
1.524,  air  being  1  ;  and  8.5  cubic  feet  therefore  will 
make  one  pound,  and  43.89  pounds  will  give  a  volume 
of  375  cubic  feet. 

The  highest  pressure  at  which  steam,  air,  or  gas  can 
be  used  to  advantage  upon  the  piston  of  an  engine  is 
about  14  atmospheres.  If  higher  pressures  are  devel- 
oped, they  must  be  reduced  to  about  210  pounds  before 
admission  to  the  cylinders,  as  has  been  shown. 

375  cubic  feet  condensed  to  14  atmospheres  =  27 
cubic  feet. 

Now,  if  27  cubic  feet  of  gas  were  admitted  to  a  cyl- 
inder 27  feet  long,  to  act  on  a  piston  of  1  square  foot 
area  and  cut  off  at  T*T  of  the  stroke,  the  gas  would  be 
used  in  the  most  economical  manner  to  secure  foot- 
pounds of  work,  and  the  number  of  foot-pounds,  at 
each  stroke,  would  be  found  by  multiplying  the  area 
of  the  piston  by  the  average  pressure  (210  x  .260)  and 
by  the  length  of  stroke,  27.  Thus,  144  x  210  x  0.260 
X  27  =  212,274  foot-pounds. 

But  1  thermal  unit  =»  772  foot-pounds,  and  212,274  -f- 
772  =  275  thermal  units  of  work  developed  in  each  stroke. 

27  cubic  feet  cut  off  at  -^  will  be  sufficient  for  14 
strokes,  and  the  43.89  pounds  of  carbonic  acid  will 
therefore  develop  275  x  14  =  3850  units,  at  a  cost  of 
$1.24. 

But  1  pound  of  coal  will  develop  in  combustion  over 
13,000  units,  at  a  cost  of  2J  mills  per  pound,  at  $5  per 
ton;  therefore,  1  pound  of  coal  will  produce  a  mechanical 
effect,  at  a  cost  of  2J  mills,  3.37  times  greater  than  the 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       149 

44  pounds  of  carbonic  acid,  at  a  cost  of  $1.24.  In  other 
words,  it  would  require  148.28  pounds  of  carbonic  acid 
gas,  costing  $4.18,  to  produce  the  same  mechanical  effect 
in  foot-pounds  as  could  be  obtained  from  the  combus- 
tion of  1  pound  of  coal,  costing  2J  mills. 

Instead  of  being  an  economical  source  of  power,  the 
gas  would  cost  nearly  1700  times  as  much  as  the  coal, 
measured  by  the  mechanical  effect  produced. 

The  same  article  stated  that  the  gas  could  be  collected, 
compressed,  and  used  over  again.  It  would  be  practi- 
cally impossible  to  collect  it,  and  if  it  could  be  collected 
no  advantage  could  be  gained,  as  it  would  be  impossible 
to  obtain  from  the  gas,  when  compressed,  an  amount  of 
units  equal  to  more  than  half  that  expended  in  the  com- 
pression. Air  is  the  only  gas  that  is  suitable  for  com- 
pression as  a  motive  power,  and  air  costs  nothing. 

Such  schemes  for  producing  power  as  that  which  has 
been  considered  would  be  unworthy  of  notice  were  it 
not  that  many  persons  are  deceived  by  plausible  repre- 
sentations and  induced  to  contribute  money  for  develop- 
ment, resulting  in  serious  losses  through  ignorance  of 
the  natural  laws  upon  which  such  operations  are  de- 
pendent. 


XVI. 

TRANSMISSION  OF   POWER   BY  MEANS   OF  PIPES. 

THE  use  of  compressed  air  as  a  substitute  for  steam 
in  the  production  of  power  requires  -its  transmission 
often  to  very  considerable  distances,  and  the  losses  in 
transmission  become  an  important  subject  for  determina- 


150  STEEET   RAILWAY    MOTORS. 

tion.  Unlike  steam,,  there  is  no  loss  by  condensation 
whatever  may  be  the  distance  to  which  the  air  is  carried  ; 
or  if  pipes  and  reservoirs  are  tight  there  is  no  loss,  how- 
ever long  the  air  may  remain  unused. 

Having  been  employed  professionally  to  investigate 
and  report  upon  the  practicability  of  the  transmission  of 
steam  for  heating  purposes  by  the  system  of  Bird  sell 
Holly,  of  Lockport,  N.  Y.,  the  writer  discovered,  in  the 
course  of  experiments  and  observations,  that  a  relation 
existed  between  the  discharges  of  elastic  and  inelastic 
fluids,  such  that  the  discharges  of  any  elastic  fluid,  as 
air  or  steam,  could  be  readily  determined  from  the 
discharge  of  water  under  like  conditions,  and  the  law 
which  defines  the  relations  between  water  and  any  elastic- 
fluid  may  be  thus  enunciated  : — 

The  discharge  of  elastic  fluids  through  long  pipes  is 
equal  to  the  corresponding  water  discharge  under  like 
conditions  multiplied  by  the  square  root  of  the  number 
which  expresses  the  relative  density  as  compared  with 
water,  and  the  product  multiplied  again  by  the  square 
root  of  the  initial  density  in  atmospheres.  The  result 
will  give  the  volume  of  discharge  under  atmospheric 
pressure. 

As  the  subject  of  the  transmission  of  elastic  fluids 
through  pipes  is  of  interest  and  importance  in  connection 
with  the  use  of  compressed  air  for  power,  and  especially 
for  the  transmission  of  power  to  operate  motors  on  ex- 
tended lines,  a  few  pages  devoted  to  the  consideration 
of  this  subject  and  to  the  demonstration  of  the  law 
that  has  been  enunciated  will  not  be  considered  inap- 
propriate. 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       1  51 

DISCHARGE  OF  FLUIDS  THROUGH  ORIFICES. 

The  velocity  acquired  by  a  body  falling  freely  in 
vacuo  is  eight  times  the  square  root  of  the  height,  both 
the  velocity  and  height  expressed  in  feet  and  time  in 
seconds. 

The  velocity  of  fluids  escaping  through  an  orifice  fol- 
lows the  law  of  falling  bodies,  and  is  expressed  by  eight 
times  the  square  root  of  the  height  in  feet. 

This  result  is  not  practically  correct,  as  the  discharge 
is  less  than  would  be  due  to  the  full  area  of  the  orifice. 
The  particles  in  escaping  reduce  the  diameter  by  con- 
traction of  vein  to  0.8,  and  the  area  to  about  0.64  of  the 
full  area  of  the  orifice. 

In  the  case  of  elastic  fluids  the  density  of  a  vertical 
column  would  diminish  from  the  bottom  to  the  top,  and 
the  height,  in  estimating  the  volume  of  discharge,  must 
be  taken  as  that  of  a  column  of  uniform  density,  the 
height  of  which  would  be  equal  to  the  pressure  at  the 
orifice. 

Where  the  discharge  is  made  into  a  receiver  contain- 
ing the  same  fluid  at  a  reduced  pressure,  the  differences 
in  pressure  must  be  taken  in  determining  the  height  and 
velocity. 

A  remarkable  exception  to  this  law  has  been  an- 
nounced in  a  work  on  steam,  published  in  London,  1875, 
by  D.  K.  Clark,  in  which  it  is  stated  that  the  applica- 
tion of  the  formula  for  gravity  is  limited  to  cases  in 
which  the  resisting  pressure  does  not  exceed  about  58 
per  cent,  of  pressure  which  causes  the  flow.  The  flow 
is  neither  increased  nor  diminished  by  reducing  the 
resisting  pressure  below  about  58  per  cent,  of  the  abso- 


152  STEEET    RAILWAY    MOTORS. 

lute  pressure  in  the  boiler.  For  example,  the  same 
weight  of  steam  would  flow  from  a  boiler  under  a 
total  pressure  of  100  pounds  to  the  square  inch,  into 
steam  of  58  pounds  total  pressure,  as  into  the  atmo- 
sphere. 

The  author  states  that  for  this  remarkable  discovery 
he  is  chiefly  indebted  to  the  experiments  made  by  Mr. 
R.  D.  Napier,  and  refers  to  a  report  on  safety-valves 
made  to  the  Institution  of  Engineers  and  Ship-builders  in 
Scotland  in  1874. 

Desiring  to  obtain  further  information  on  this  subject, 
I  requested  Prof.  Geo.  W.  Plympton,  former  editor  of 
Van  Nostrand's  Engineering  Magazine,  to  see  if  he 
could  find,  in  the  libraries  in  New  York,  the  report 
on  safety-valves  referred  to.  In  a  letter  received  in 
reply,  he  stated  that  he  found  the  report  at  the  rooms  of 
the  Society  of  Civil  Engineers,  but  that  it  merely  quoted 
the  deductions  of  the  experimenter,  Napier,  in  the  same 
form  as  previously  given.  Prof.  Plympton  also  stated 
that  Rankine  discussed  the  same  subject,  and  that 
Napier  contributed  articles  to  Engineering  on  this  topic 
in  1872. 

If  the  conclusions  of  Napier  be  accepted  as  correct, 
it  would  appear  that  steam  escaping  from  an  orifice  into 
the  air  at  a  pressure  of  25  pounds,  acquires  a  velocity  of 
about  800  feet  per  second,  and  attains  a  maximum  of 
875  feet,  after  which  the  velocity  remains  constant,  how- 
ever great  the  pressure.  Some  direct  experiments  on  the 
velocity  of  steam  escaping  from  an  orifice,  just  completed 
by  Messrs.  Holly  and  Gaskill,  of  Lockport,  give,  in  one 
case,  951  feet  per  second,  and  in  another  1023  feet  per 
second. 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       153 

It  is  not  difficult  to  understand  that  the  velocity  might 
be  constant,  for  the  velocity  is  that  due  to  the  height  of 
a  column  of  uniform  density  whose  weight  is  equal  to 
the  pressure.  Now,  if  the  pressure  should  be  doubled, 
the  density  and  weight  of  a  uniform  column  would  also 
be  doubled,  and  the  height  which  determines  the  velocity 
would  remain  constant ;  but  the  declaration  that  the 
weight  of  steam  discharged  remains  constant  requires 
confirmation. 

The  efflux  of  steam  through  an  orifice  fortunately  has 
but  little  influence  on  the  discharge  through  long  pipes 
where  the  velocities  are  comparatively  low,  and  the 
results  will  not  be  aifected  by  any  uncertainties  in  regard 
to  the  velocity  of  flow  through  orifices. 

RESISTANCE  OF  LONG  PIPES  TO*  THE  FLOW  OF 
ELASTIC  FLUIDS. 

This  was  one  of  the  most  important  subjects  connected 
with  the  practical  and  extended  application  of  the  Holly 
system,  and  one  upon  which  comparatively  little  infor- 
mation could  at  that  time  be  obtained  from  books.  Mr. 
Holly  stated  that  he  had  searched  in  vain  for  any  reliable 
information  on  the  subject,  and  the  only  table  found 
published  was  headed,  "  friction  of  air,  steam,  and  gas 
in  long  pipes/'  without  any  recognition  of  the  influence 
of  density,  which  would  cause,  the  results  to  vary  in  the 
wide  range  of  from  4  to  10.  It  is  proposed,  therefore, 
to  give  this  subject  careful  consideration. 

When  engaged  in  maturing  plans  for  tunnelling  the 
Hoosac  mountain,  the  writer  made  a  series  of  experi- 
ments on  the  friction  of  air  in  a  tunnel  at  Wiconisco. 


154  STREET    RAILWAY    MOTORS. 

A  pipe  of  wood  was  constructed  about  1400  feet  long 
and  110  square  inches  in  area.  The  current  of  air  was 
produced  by  a  vacuum  fan,  driven  by  a  steam  engine, 
the  velocities  determined  by  an  electrical  apparatus,  and 
the  results  demonstrated  : — 

1.  That  the  resistance  was  in  proportion  to  the  square 
of  the  velocity. 

2.  That  the  resistance  was  inversely  as  the  diameter. 

3.  That  the  power  required  to  pass  a  given  quantity 
of  air  through  pipes  of  different  diameters  was  inversely 
as  the  fifth  powers  of  the  diameters.    As  a  consequence, 
it  was  found  that  it  would  require  a  million  times  more 
power  to  pass  the  same  quantity  of  air  through  a  pipe 
one  foot  in  diameter  than  would  be  required  if  the  pipe 
were  10  feet. 

At  the  Mt.  Cenig  tunnel  it  was  decided  to  use  com- 
pressed air  as  a  motor,  and  the  preparatory  experiments 
were  made  at  government  expense  by  a  commission  of 
gentlemen  of  eminent  scientific  attainments,  consisting 
of  Messrs.  DeNerache,  Giulio,  Menebrea,  Rura,  and 
Sella. 

Special  experiments  were  instituted  on  long  lines  of 
metallic  pipe,  continued  by  rubber  hose,  and  observations 
made  on  pressure  and  velocity.  The  elastic  force  of  the 
fluid  was  ascertained  at  the  commencement  and  end  of 
the  pipe,  and  a  curve  traced  for  the  interpretation  of  the 
results,  from  which  a  table  was  prepared,  giving  initial 
velocities  in  metres  per  second,  diameters  of  pipes  in 
decimals  of  a  metre,  and  friction,  or  loss  of  tension  in 
millimetres  of  a  column  of  mercury. 

A  copy  of  the  report  of  this  commission  was  procured 
through  the  kindness  of  Professor  Gillespie ;  from  it  a 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       155 

table  was  calculated  in  which  pressures  were  expressed 
in  pounds,  velocities  in  feet  per  second,  and  lengths  in 
miles. 

In  using  tables  for  the  friction  of  elastic  fluids  through 
pipes,  one  peculiarity  is  observable.  With  dense  fluids, 
such  as  water,  the  head  is  an  important  element  in 
calculating  the  loss  by  friction,  but  with  elastic  fluids 
the  initial  velocity  is  given  and  the  head  is  not  a  neces- 
sary datum  in  the  calculations  where  there  is  a  free  dis- 
charge ;  but  when  there  is  back  pressure  it  would  seem 
that  the  initial  density,  as  also  the  initial  velocity,  must 
be  considered. 

The  explanation  is  this  :  Suppose  pressure  should  be 
quadrupled,  the  fluid  being  supposed  perfectly  elastic 
would  be  quadrupled  in  density,  and  the  power  required 
to  move  it  at  a  given  velocity  which*  measures  the  re- 
sistance would  be  quadrupled  also,  or  would  be  as  1  to 
4;  but  the  velocity,  being  as  the  square  root  of  the  head 
or  pressure,  would  be  doubled  also  by  quadrupling  the 
head  or  pressure,  and  would  be  as  1  to  2,  and  the  re- 
sistance would  be  (I)2  :  (J)2,  or  J.  Hence,  while  the 
increase  of  density  would  quadruple  the  resistance,  the 
reduction  of  velocity  due  to  that  pressure  would  reduce 
it  to  one-fourth,  or  the  resistance  of  a  given  length  with 
a  given  velocity  would  be  constant. 

This  conclusion  may  be  reached  by  another  process  of 
reasoning  :  Where  a  fluid  is  discharged  through  a  long 
pipe  the  pressure  at  the  commencement  is  the  head  in 
the  reservoir ;  at  the  end  where  it  discharges  it  is  noth- 
ing, or  simply  the  head  due  to  the  velocity.  The 
hypothentise  of  a  triangle,  of  which  the  base  represents 
the  length  and  the  perpendicular  the  head,  will  be  the 


156  STREET   RAILWAY    MOTORS. 

hydraulic  gradient ;  and  so  long  as  head  divided  by 
length  or  hydraulic  gradient  is  constant,  the  velocity  is 
constant  and  the  discharge  also.  Now,  if  head  should 
be  quadrupled,  velocity  remaining  constant,  length  must 
be  quadrupled  also,  and  head  divided  by  length,  which 
represents  the  friction  per  unit  of  length,  will  be  con- 
stant also,  and  will  vary  in  the  same  pipe  with  the 
square  of  the  velocity. 

In  determining  the  resistance  of  different  elastic  fluids, 
density  is  an  important  element,  which  appears  some- 
times to  have  been  overlooked.  That  it  is  important 
will  be  obvious  from  the  consideration  that  the  power 
required  to  move  a  body  is  in  proportion  to  the  weight 
of  the  body  moved,  and  the  weight  is  in  proportion  to 
density  ;  if  density  should  be  doubled  the  resistance  will 
be  doubled,  and  if  reduced  the  resistance  will  be  reduced 
proportionately. 

Let  us  imagine  two  elastic  fluids  of  equal  height,  but 
whose  densities  compare  as  1  to  2.  As  the  heights  are 
equal,  the  velocities  of  discharge  will  be  equal.  On  a 
line  as  above,  representing  a  unit  of  length,  draw  a  per- 
pendicular, 1,  and  complete  the  triangle ;  draw  a  second 
perpendicular,  2,  and  complete  the  second  triangle.  The 
perpendiculars  at  any  point  will  represent  the  pressure 
at  that  point,  and  the  areas  of  the  triangles  will  be 
proportioned  to  the  total  resistance.  As  these  areas 
compare  as  1  to  2,  so  will  the  loss  by  friction  be  as  1  to 
2,  or  as  the  densities. 

The  following  are  extracts  from  the  report  on  the 
Holly  system  : — 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       1  57 

DEMONSTRATION  OF  THE  LAW  OF  THE  DISCHARGE 
OF  ELASTIC  FLUIDS  THROUGH  LONG  PIPES. 

The  quantity  of  steam  discharged  through  a  pipe  of  a 
given  length  and  diameter  under  a  given  pressure,  and 
the  losses  by  friction  and  radiation,  are  questions  which 
lie  at  the  very  foundation  of  the  successful  application 
of  the  Holly  system,  and  without  which  it  will  be  im- 
possible to  form  plans  and  prepare  estimates  for  the 
supply  of  any  given  district,  with  confidence  that  mis- 
takes will  not  be  committed,  that  the  plans  provided 
will  not  prove  insufficient,  and  that  mains  will  not  re- 
quire to  be  torn  up  or  duplicated  after  the  lesson  has 
been  learned  from  dearly-bought  experience  that  sound 
theory  should  have  taught  in  advance. 

As  it  has  been  found  impossible  to  procure  from  any 
known  authors  on  hydraulics  or  pneumatics  just  that 
practical  information  that  will  meet  the  requirements  of 
the  present  investigations,  and  as  the  writer  has  ven- 
tured to  enunciate  a  fundamental  law  on  which  the 
solution  of  all  problems  relating  to  steam  transmission 
must  depend,  and  which  is  not  only  not  contained  in 
books,  but  is  in  conflict  with  rules  given  by  some 
popular  authors,  no  apology  will  be  necessary  for  the 
time  and  space  devoted  to  a  demonstration  of  the  law  in 
question.  This  law  may  be  thus  enunciated  : — 

The  discharge  of  steam,  air,  or  any  elastic  fluid,  under 
pressure  through  long  pipes  and  at  the  volume  due  to 
atmospheric  tension,  is  equal  to  the  water  discharged 
under  like  conditions  multiplied  by  the  square  root  of 
the  number  which  expresses  the  relative  density  at 
atmospheric  tension,  as  compared  with  water,  multiplied 


158 


STREET    RAILWAY    MOTORS. 


also  by  the  square  root  of  the  initial  pressure  in  atmo- 
spheres. 

For  example,  air  is  836  times  lighter  than  water 
under  ordinary  atmospheric  tension,  and  if  n  =  number 
of  atmospheres  of  initial  pressure,  then  the  water  dis- 
charged, as  determined  by  the  usual  formula,  multiplied 
1/836  =  29  multiplied  byj/w,  will  give  the  discharge  of 
air ;  and  if  the  discharge  of  steam  is  required  the  mul- 
tiplier will  be  |/1712  =  42|  x  yV. 

If,  then,  n  should  be  4  atmospheres  total,  including 
atmospheric  pressure,  the  difference  of  head  to  be  used 
in  the  determination  of  the  water  discharge  would  be  3 
atmospheres,  and  water  discharge  X  42  x  "|/4  =  water- 
discharge  x  84  =  discharge  of  steam. 

In  like  manner,  if  the  total  pressure  should  be  9 
atmospheres  =  120  pounds  indicated  pressure,  the  dis- 
charge of  steam  would  be  =  water  discharge  X  42  -j/9 
=  126  times  the  water  discharge  under  an  equal  head. 


And,  in  general,  if  w  =  the  water  discharge  under 
any  given  head,  length,  and  diameter  of  pipes,  d  =  ratio 
of  density  of  any  elastic  fluid,  as  compared  with  water 
and  at  the  volume  due  to  atmospheric  tension,  and  n  = 
number  of  atmospheres  of  initial  pressure,  then  will  the 
discharge,  as  compared  with  water,  and  ^  the  volume 
due  to  atmospheric  tension,  be  =*  w  X  \/nd. 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES. 

Let  A  B  represent  a  pipe  of  any  given  length,  say  one 
mile,  and  A  C  represent  the  pressure,  say  60  pounds. 
The  discharge  of  water  at  B,  in  cubic  feet  per  second,  is 
given  by  the  formula  : — 

(i  =  .0762  i/T6 1/| 

\\  *<7  "^  **& 

d  =  diameter  in  inches,  H  =  head  in  feet,  or  the  dififer^ 
ence  in  head  when  discharging  against  a  lower  pressure,  ^ 
and  L  =  length  in  feet. 

If  A  C  =s  60  pounds,  the  head  of  water  would  be 
60  x  2.31  =  138.6  feet,  and_the  discharge  with  a  con- 
stant length  would  be  as  1/H,  or  as  "1/138.6,  and  the 
area  of  a  triangle  of  which  A  B  is  the  base  and 
1/T38.6  as  the  altitude,  would  be  proportionate  to  the 
water  discharge  or  A  B  x  "1/138.6. 

Now  suppose  that  the  fluid  discharging  at  B  should 
be  steam  instead  of  water  under  60  pounds  indicated 
pressure,  the  actual  pressure  would  be  75  pounds,  the 
number  of  atmospheres  5.  The  initial  density  five  times 


1712 


that  of  steam  under  atmospheric  pressure,  or  —  =  342, 
and  the  head  due  to  a  pressure  of  60  pounds  =  138.6  X 
342  =  47,401  feet. 

The  discharge  being  proportioned  to  the  square  root 
of  the  head,  would  be  as  1/138.6  X  342,  or  as  -[/ 138.6 
I/  1Z1?  and  if  A  B  as  before  =  base  of  a  triangle,  and 


47,401  =  altitude,  the  discharges  being  as  the  square 
root  of  the  altitude,  will  be  as  the  area  of  a  triangle 
whose  base  is  A  B  and  altitude  = 


|/47401==  -j/138.6  *  -J/1712 -i/5- 
The  water  discharges  and  steam  discharges  being  as 
the  areas  of  these  triangles  having  the  common  base  A  B, 


160  STREET    RAILWAY   MOTORS. 

will  compare,  as  1/138.6  is  to  1/138.6  1/7712  -*-  1/5^ 
or  if  the  water  discharge  be  taken  as  unity,  then  as  1  is 
to  1/1712  -f-  1/^5. 

But  this  expression  gives  the  discharge  under  initial 
density,  and  if  the  discharge  is  required  at  atmospheric 
tension,  which  is  always  desirable  for  the  sake  of  uni- 
formity, the  result  must  be  multiplied  by  5,  and  the  ex- 
pression becomes  1/1712  x  5.-*-  1/5  =  1/1712  x  1/5, 
as  previously  stated,  or  generally  as  ~\/  n  d. 

The  head  due  to  velocity  has  not  been  considered,  as 
in  questions  relating  to  discharges  through  long  pipes  it 
is  so  insignificant  as  compared  with  the  head  due  to  fric- 
tion, that  it  may  safely  be  neglected.  It  would  not  ex- 
ceed, generally,  a  small  fraction  of  a  pound ;  but  if  great 
accuracy  is  desired  the  head,  in  feet,  is  readily  deter- 
mined, and  is  —  in  which  v  —  initial  velocity,  and  the 

head  divided  by  the  number  of  feet  at  initial  density 
required  to  make  one  pound,  will  give  the  pressure  in 
pounds  required  for  this  velocity  v,  which  is  in  addi- 
tion to  friction.  Suppose  the  length  of  the  pipe  should 
be  increased,  and  draw  a  line  from  D  to  the  end  of  the 
pipe,  intersecting  the  line  n  B  at  P.  The  triangle  D  n  P 
will  be  cut  off,  the  perpendiculars  of  which  will  repre- 
sent the  loss  of  head  by  friction,  and  the  square  root  of 
the  area,  the  discharge  in  cubic  feet,  and  the  same  rule 
holds  good  if  the  length  should  be  less  than  A  B. 

Important  Observation. — Although  almost  self-evident 
yet,  as  very  erroneous  ideas  seem  to  have  been  enter- 
tained in  regard  to  the  friction  of  pipes,  it  is  necessary 
to  state,  emphatically,  that  in  the  discharge  of  fluids 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       161 

through  pipes — whether  the  fluids  be  elastic  or  non- 
elastic — the  whole  of  the  head,  less  that  due  to  velocity, 
is  absorbed  by  friction ;  and  where  there  is  a  free  dis- 
charge there  is  no  pressure  whatever  at  the  open  end  of 
the  pipe. 

Referring  again  to  the  diagram,  if  A  B  is  a  pipe  a 
mile  long  and  discharges  water,  steam,  or  air  freely  at  B 
under  an  initial  pressure  at  A  =  60  pounds,  there  will 
be  no  indicated  pressure  whatever  at  B  unless  the  dis- 
charge be  throttled,  and  the  reduction  of  pressure  from 
A  to  B  will  follow  the  line  of  the  hypothenuse,  and  the 
pressure  at  any  point  will  be  represented  by  the  perpen- 
dicular. If,  for  example,  the  initial  pressure  be  repre- 
sented by  A  D,  the  pressure  at  B  will  be  o,  the  total  loss 
of  pressure  by  friction  in  the  distance  A  B  will  be  60 
pounds.  At  any  point  P  the  pressure  will  be  repre- 
sented by  the  perpendicular  O  P,  and  the  loss  of  pres- 
sure by  O  m. 

But  if  the  pipe  is  not  discharging  freely  at  B,  the 
conditions  will  be  very  materially  changed,  and  a  large 
percentage  of  the  fluid  may  be  drawn  off  at  intermediate 
points  without  affecting  very  seriously  the  pressure  at  B, 
due  to  the  initial  head  if  the  pipe  were  closed. 

It  has  been  asserted  as  the  result  of  observation  that 
at  Detroit  a  mile  of  pipe  6  inches  in  diameter  was  laid, 
and  notwithstanding  the  fact  that  a  large  number  of 
consumers  were  using  steam  at  intermediate  points,  the 
pressure  at  the  boiler  and  at  the  end  was  precisely  the 
same  ;  and  the  inference  deduced  therefrom  was  that 
steam  can  be  carried  almost  any  distance  with  a  loss  of 
power  that  is  scarcely  appreciable. 

This  is  a  great  mistake,  and  it  would  be  a  fatal  error 
11 


162  STREET    RAILWAY    MOTORS. 

if  works  were  planned  and  constructed  with  any  such 
ideas.  If  the  observed  pressures  at  the  two  ends  of  the 
pipe  at  Detroit  were  the  same,  it  resulted  from  two 
causes:  First,  a  want  of  sensitiveness  in  the  gauges, 
which  often  do  not  indicate  within  ten  pounds  of  the 
correct  pressure  ;  and  second,  the  intermediate  consumers 
were  drawing  off  a  small  percentage  of  the  capacity  of 
the  pipe. 

I  will  endeavor  to  elucidate  this  subject  by  a  simple 
and  practical  illustration  : — 

Suppose  a  pipe  be  taken  6  inches  diameter,  one  mile 
long,  and  60  pounds  initial  pressure.  The  water  dis- 
charge will  be  1.1  cubic  feet  and  the  steam  discharge 
=  l.ll/1712xi/5  =102  cubic  feet  of  steam  per  second. 

A  horse-power  for  steam  heating  purposes  has  been 
taken  as  one  cubic  foot  of  water  evaporated  per  hour, 
and  one  cubic  foot  of  water  =1712  cubic  feet  of  steam. 
Therefore,  1712  H-  3600  =0.472  cubic  feet  per  second  = 
one  horse-power. 

And  102-j-0.472=216  horse-power  =  maximum  capa- 
city of  1  mile  of  6-inch  pipe  under  60  pounds  pressure. 

But  suppose  the  end  B  of  the  pipe  is  closed,  and  at 
the  point  P  =  J  of  a  mile  from  A,  one-fourth  of  the 
whole  capacity  of  the  pipe  is  drawn  off,  how  will  the 
pressure  at  B  be  affected  ? 

If  discharging  freely  at  B,  the  pressure  at  P,  at  J 
A  B  will  be  f  of  60  pounds,  or  45  pounds,  and  the  loss 
of  pressure  will  be  represented  by  Om=15  pounds. 
But  if  the  end  B  is  closed,  and  the  discharge  at  P  is  J 
capacity  of  pipe,  then  the  velocity  from  A  to  P  will  be 
reduced  to  J,  and  the  friction,  which  is  as  the  square  of 
the  velocity  to  (J)2  =tV,  and  the  loss  of  head  from 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       163 

taking  off  25  per  cent,  of  the  whole  capacity  of  the  pipe 
at  P  would  be  15  x  tV^rf  °f  one  Pouncl>  an^  the  pres- 
sure at  B  would  be  59T^  pounds  as  compared  with  an 
initial  pressure  of  60  pounds. 

If  one-half  the  whole  capacity  of  the  pipe  should  be 
drawn  off  at  the  middle  point,  or  if  there  should  be  an 
equivalent  thereto  discharged  the  reduction  of  pressure 
at  the  extreme  end,  instead  of  being  30  pounds,  or  one- 
half,  would  be  ^  x(J)2  =  7J  pounds,  and  the  pressure 
remaining  would  be  52  J  pounds. 

These  results,  deduced  from  purely  theoretical  con- 
siderations, seem  to  be  entirely  consistent  and  reasonable ; 
but  it  is  important  to  test  them  by  actual  and  careful 
experiments. 

The  experiments  of  Mr.  Holly  and  Mr.  Gaskill  at 
Lockport  were  made  under  circumstances  peculiarly 
favorable  to  accuracy.  A  large  engine  cylinder  was 
used  as  a  meter ;  the  contents,  including  clearance,  were 
8.64  cubic  feet ;  the  number  of  cylinders  discharged  per 
minute,  66 ;  cubic  feet  per  minute,  570 ;  distance  from 
boiler  equivalent  to  168  feet  of  2-inch  pipe  in  frictional 
resistance;  boiler  pressure,  50  pounds;  cylinder  pressure, 
30  pounds ;  loss  by  friction,  20  pounds. 

From  these  data  let  us  determine  the  friction  in  one 
mile  of  6-inch  pipe  under  a  head  or  pressure  of  60  pounds. 

If  Mr.  Holly  gets  a  discharge  of  570  cubic  feet  per 
minute  in  a  pipe  2  inches  diameter  and  168  feet  long, 
the  discharge  per  second  will  be  570  -+-  60  =9.5,  under 
total  initial  pressure  of  50  +  15=65  pounds;  as  the 
discharge  is  in  proportion  to  the  square  root  of  the  length, 
the  discharge  in  one  mile  =  9.5  X  T/F26A  =  1-78  cubic 
feet. 


164  STREET    RAILWAY    MOTORS. 

If  the  discharge  is  1.78  cubic  feet  in  a  2-inch  pipe, 
the  discharge  being  as  the  square  root  of  the  fifth  power 
of  the  diameter,  it  will  be  in  a  6-inch  pipe  1.78  X  15.6 
=  27.76.  If  the  discharge  be  27.76,  under  30  pounds, 
and  under  initial  pressure  of  50  pounds,  the  discharge 
at  atmospheric  tension  under  initial  pressure  of  60 
pounds,  would  be  27.46  x  ^x  1/f  =  91.6  cubic  feet 
per  second,  as  deduced  from  experiment  of  Messrs. 
Holly  and  Gaskill  through  a  pipe  obstructed  by  several 
bends. 

We  will  now  examine  what  should  have  been  the  dis- 
charge through  a  pipe  one  mile  long,  six  inches  diameter, 
under  60  pounds  head,  as  deduced  from  the  theoretical 
law  heretofore  enunciated. 

The  water  discharge  is  1.1  cubic  feet  per  second,  and 

1.1  X  1712x  1/^=102,  the  theoretical  discharge, 
and.  the  difference,  10.6,  is  fully  explained  by  the  eight 
bends  in  the  pipe  through  which  the  steam  was  trans- 
mitted in  the  experiment. 

This  result,  giving  a  greater  theoretical  than  actual 
discharge,  is  the  more  gratifying  because  it  has  generally 
been  believed  that  theory  was  unreliable,  and  that  the 
actual  results  as  deduced  from  observation  and  experi- 
ment were  far  in  excess  of  the  capacity  and  pressure  as 
given  by  the  books. 

This  is  true,  because  in  stating  a  rule  the  books  did 
not  always  state  the  conditions  under  which  it  was  ap- 
plicable, as,  for  example,  the  rule  that  the  discharge  of 
air  is  equal  to  30J  times  the  discharge  of  water  under 
like  conditions,  is  true  only  at  one  initial  pressure,  and 
that  a  very  low  one,  while  under  high  pressures  the 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       165 

error  from  its  application  may  be  several  hundred  per 
cent. 

If  theory  is  not  sustained  by  observation  and  experi- 
ment, it  only  proves  that  the  theory  is  defective,  and 
that  the  true  law  has  not  been  discovered  ;  but  that  there 
are  natural  laws  is  unquevStionable,  and  these  laws,  as 
applicable  to  pneumatics,  are  as  immutable  as  those  of 
gravity. 

Practical  men,  proceeding  without  a  knowledge  of 
these  laws,  are  like  mariners  at  sea  without  chart  or 
compass. 

I  propose  to  show  that  the  law  of  discharge  that  has 
been  here  given  is  further  verified  by  the  careful  and 
elaborate  experiments  made  at  the  Mt.  Cenis  tunnel. 


FRICTION  OF  AIR  IN   PIPES  AS   DETERMINED  FROM 
THE  EXPERIMENTS  AT  THE  MT.  CENIS  TUNNEL. 

The  scientific  commission,  appointed  to  conduct  these 
experiments,  reported  the  following  table  as  a  condensa- 
tion of  their  results  : — 

Loss  of  Tension  per  1000  metres  of  Pipe,  expressed  in 
Millimetres  of  a  Column  of  Mercury. 


Velocity  of  air  at  the  en- 

Diameter of  pipes  in  the  clear,  in  decimals  of  a  m'etre. 

trance  of  the  pipe,  in 

metres,  per  second. 

0.10 

0.15 

0.20 

0.25 

0.30 

0.35 

1 

6 

4 

3 

3 

2 

2. 

2 

26 

18 

13 

11     !       9 

8 

3 

62 

42 

31 

25 

21 

18 

4 

108 

72 

54 

44 

36 

31 

5 

167 

112 

84 

67 

56 

48 

6 

233 

156 

117 

94 

78 

67 

166  STREET    RAILWAY    MOTORS. 

An  inspection  verifies  these  laws  :  — 

1.  Friction  inversely  as  diameters. 

2.  Friction  directly  as  squares  of  velocities. 
To  which  may  be  added  two  other  la\vs  :  — 

3.  Friction  directly  as  the  length. 

4.  Friction  directly  as  the  density. 

In  comparison  with  other  results  the  friction  of  1  mile 
of  6-inch  pipe  with  initial  velocity,  20  feet  will  be  de- 
duced from  this  table. 

Assume  any  number,  say  a  pipe  0.2  of  a  metre  diam- 
eter and  5  metres  velocity,  the  loss  in  millimetres  of 
mercury  is  84.2  of  a  metre  =  7.874  inches  ;  5  metres  per 
second=  16.4  feet;  1000  metres  =3281  feet;  1  milli- 
metre =0.03937  inches. 

7.874      202      .03937     5280     _, 
Then  84  x  --  x  x  —       x          -  5.1  pounds, 


as  the  resistance  of  air,  and  for  steam  2.5  pounds  per  mile, 
assuming  loss  of  tension  to  be  in  proportion  to  density. 

We  will  now  apply  the  law  as  deduced  from  the  hy- 
draulic discharge  :  — 

The  discharge  of  water  under  a  head  of  60  pounds, 
length  1  mile  and  diameter  6  inches,  is  1.1  cubic  feet  per 
second. 

Air  is  836  times  lighter  than  water.  60  pounds 
—  5^5—5  atmospheres;  1.1  X  j/836x  1/5  =  67.87  cu_ 
bic  feet  per  second,  and  at  initial  density  =67.  87  -*-5 
=  13.57  cubic  feet,  and  initial  velocity  68  feet  per  sec- 
ond, nearly. 

Now,  if  the  loss  of  tension  with  initial  velocity  of  68 
feet  be  60  pounds,  the  loss  with  velocity  of  20  feet  will 

202 
be  60  X  —  =  5.1  pounds. 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       167 

This  is  precisely  the  loss  of  tension  in  one  mile  of 
6-iuch  pipe  discharging  air  under  an  initial  velocity  of 
20  feet  per  second,  as  deduced  from  the  experiments  of 
the  Mt.  Cenis  Tunnel  Commissioners. 

The  law  of  discharge,  above  stated,  seems  to  be  com- 
pletely verified  and  established,  both  by  the  experiments 
in  Europe  and  those  made  by  Mr.  Holly,  at  Lockport, 
with  the  engine  metre,  and  I  think  can  be  safely  relied 
upon  as  a  basis  of  calculation  of  capacity  of  mains  and 
losses  by  friction  in  transmission. 

The  following  table  will  be  convenient,  giving  the 
discharge  of  steam  at  the  volume  of  atmospheric  tension, 
the  corresponding  water  discharge  under  same  head, 
diameter  and  length  being  taken  as  unity,  and  pressures 
varying  by  half  atmospheres  from  1  to  10  : — 

Volume  of 
Discharge. 

....  41.4 
....  50.7 
....  58.6 
....  65.5 
....  71,7 
....  77.3 
....  82.8 
....  88.2 
....  92.5 
....  97.3 

....  101.4 

....  105.9 

....  109.6 

....  113.2 

....  117.0 

....  120.5 

....  124.1 

....  127.7 
130.8 


Pressure  in 

Initial 

Atmospheres. 

Densities. 

1          ... 

.     .       1712 

IT      •     •     • 

.     .       1141 

2        ... 

.     .         856 

2*       ... 

.     .         685 

3         ... 

571 

31       ... 

.     .        489 

4         ... 

.     .        428 

41       ... 

.     .        381 

5         ... 

342 

5*       .     .     . 

.     .        311 

6         ... 

.     .         285 

6^       ... 

.     .         263 

7        ... 

.     .         245 

7^       ... 

.     .        228 

8         ... 

.     .        214 

8J 

.     .         201 

9         ... 

.     .         190 

9*       ... 

.     .         180 

10         .     .     . 

.     .        171 

168  STREET    RAILWAY    MOTORS. 

TABLE  OF  THOMAS  Box. 

In  the  valuable  work  on  heat  by  Thomas  Box,  is 
given  a  table  for  the  friction  of  air,  steam,  and  gas  in 
long  pipes.  The  difference  in  density  is  not  recognized 
in  this  table,  but  it  was  probably  intended  for  air,  as 
this  fluid  was  more  particularly  under  discussion.  Under 
this  hypothesis,  the  results  will  be  compared  with  our 
assumed  standard  of  velocity,  20  feet,  length  one  mile, 
diameter  six  inches. 

The  table  gives  the  head  to  overcome  friction  with 
velocity  of  10  cubic  feet  per  minute  through  a  two-inch 
pipe  for  a  distance  of  one  yard  =0.000162  pound. 

Area  of  2-inch  pipe  =  3.1416  and  10  X^^^O.77 
=  velocity  in  feet  per  second. 

0.000162  x  1760  =  0.285120  =  friction  per  mile  in 
2-inch  pipe. 

0.285120  X  f  =  0.09504=  pounds  per  mile  friction 
in  6-inch  pipe,  velocity  0.77. 

202 
0.09504  X  ^  =  6.3  =  friction  of  air  in  a  6-inch  pipe 

for  a  distance  of  one  mile  and  velocity  20  feet  per  second. 
The  friction  of  steam  at  atmospheric  density  should 
by  the  same  rule  be  3.15  pounds,  which  is  in  excess  of 
the  results  deduced  from  formula,  from  the  Mt.  Cenis 
experiments,  and  from  other  experiments. 

FORMULA  OF  WEISBACH. 

Weisbach  gives  the  following  formula  for  the  friction 
of  air  through  long  pipes  : — 

/=  0.0256  x  ^  X  ~  in  which 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       169 

I  =  length  in  feet ; 

d  =  diameter  in  feet ; 

v  =  velocity  in  feet  per  second  ; 

/=  height  of  a  column  of  air  equal  to  the  resistance 
by  friction. 

To  test  this  formula,  assume  length  =  1  mile,  diam- 
eter 6  inches  or  0.5  of  a  foot,  and  v  =  20  feet.  Then 
friction  of  one  mile  represented  by  a  column  of  air  equals 

0.0256  x  — |°  x  fj=  1700  feet. 

But  1 700  feet  of  air,  if  at  atmospheric  tension,  would 
be  equivalent  to  about  two  feet  of  water,  weighing  less 
than  one  pound,  while  from  other  data,  both  theoretical 
and  experimental,  it  is  known  that  the  friction  is  five 
pounds.  If  the  initial,  instead  of  the  terminal,  density 
is  intended  to  be  used,  the  difficulty  is  that  there  is  no 
way  given  for  the  determination  of  this  density,  and  the 
formula,  even  if  correct,  is  practically  useless. 

So  also  the  rule  of  the  engineer's  pocket-books,  that 
the  discharge  of  air  is  30|  times  the  discharge  of  water 
under  like  conditions,  is  entirely  fallacious.  It  can  be 
true  only  at  one  pressure,  and  that  a  very  low  one,  and 
it  fails  to  recognize  the  varying  densities  of  different 
elastic  fluids  tinder  varying  pressures,  without  which 
no  rule  can  be  reliable. 

PIPES  OF  EQUIVALENT  RESISTANCES. 

When  a  line  of  pipe  consists  of  portions  whose  diame- 
ters are  not  uniform,  it  is  necessary  to  make  a  correction 
by  substituting  the  length  of  pipe  of  uniform  diameter 
that  would  give  an  equivalent  resistance. 


170 


STREET    RAILWAY   MOTORS. 


It  has  been  stated  that  where  quantity  is  constant 
and  diameter  variable  the  friction  is  inversely  as  the 
fifth  power  of  the  diameter. 

If  the  friction  in  one  mile  or  one  unit  of  length  of 
one-inch  pipe  be  taken  as  unity,  the  number  of  miles  of 
pipe  of  any  other  diameter  will  be  given  by  the  follow- 
ing table,  giving  equal  resistance  : — 


1  inch  pipe 

1*   " 

2  " 

2|   " 
3 

4    " 
5 
6 

7    " 
8 
9 
10 

11  " 

12  " 


1. 

7.5 
32. 
97.65 
243. 

.   1024. 

.   3125. 

.   7776. 

.  16807. 

.  32768. 

.  59049. 

.  100000. 

.  161051. 

.  248832. 


FORMULA  FOR  CALCULATING  TABLES  OF  Loss 
HEAD.  BY  FRICTION. 


OF 


It  has  been  seen  that  in  the  transmission  of  steam 
through  a  pipe  six  inches  in  diameter  and  one  mile  long 
the  loss  by  friction  was  2.5  pounds,  with  an  initial 
velocity  of  20  feet  per  second. 

For  any  other  length  we  have  these  laws  : — 

1.  The  friction  is  as  the  length. 

2.  The  friction  is  inversely  as  the  diameter. 

3.  The  friction  is  as  the  square  of  the  velocity. 

4.  The    friction    with   different    fluids    is    as    the 
density. 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.      ]  71 

As  a  basis  of  calculation,  it  will  be  convenient  to 
determine  the  friction  of  steam  in  1  mile  of  1-inch  pipe, 
with  an  initial  velocity  of  one  foot  per  second. 

The  friction  in  one  mile  of  6-inch  pipe,  and  initial 
velocity  20,  being  2.5  pounds  with  steam,  the  friction 
in  a  pipe  1  inch  in  diameter  will  be  2.5  X  6  =  15  pounds 
under  the  same  velocity  ;  and  the  friction  with  a  velocity 
of  20  feet  per  second  being  15  pounds,  the  friction  with  a 

velocity  of  one  foot  per  second  will  be  15  x  -—2= 0.0375. 

2\) 

For  any  other  diameter  or  velocity  the  expression 
becomes : — 

Friction  per  mile« 0.0375  x  V- 

The  initial  velocity  must  be  determined  from  the  dis- 
charge, and  the  terminal  discharge,  as  previously  stated, 
is  =  water  discharge  X  %/1712x  \/n,  in  which  n  =*  the 
atmospheres  of  pressure.  This  discharge  divided  by  n 
gives  discharge  at  initial  density,  and  the  discharge  at 
initial  density  in  cubic  feet  divided  by  the  area  in  square 
feet  will  be  initial  velocity. 


172 


STREET   RAILWAY    MOTORS. 


1  fc 


II 


^H  r<i      •  r\i     •  r^i      ••••••• 

J.tC.O.Oi-IOi— (iTJlOrH 


OOOOOOOOOOOi^O 

i-KNeQ^»«o5Ot-aoo&-O<N»a 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       173 

For  any  other  diameters  or  velocities  observe  : — 

1.  The  friction  is  as  the  square  of  the  velocity. 

2.  The  friction  is  inversely  as  the  diameter. 

3.  The  friction  is  directly  as  the  length. 

4.  The  friction  with  other  elastic  fluids  is  directly  as 
the  density. 

CAPACITY  OF  MAINS  AND  VELOCITY  OF  STEAM. 

The  discussions  in  the  preceding  pages  will  indicate  a 
manner  of  obtaining  the  discharge  of  any  elastic  fluid 
through  pipes,  and,  as  a  consequence,  its  velocity  when 
the  diameter  is  known.  It  is  only  necessary  to  calculate 
the  water  discharge  under  the  same  length,  diameter, 
and  pressure,  and  multiply  the  result  by  the  square  root 
of  the  number  expressing  the  relative  density,  multiplied 
by  the  square  root  of  the  number  of  atmospheres  of 
initial  pressure. 

The  limit  of  velocity  is  found  in  the  discharge  through 
an  orifice,  or  short  pipe  of  not  more  than  two  diameters, 
and  appears  from  the  experiments  of  Messrs.  Holly  and 
Gaskill  to  attain  its  maximum  at  about  1000  feet  per 
second,  between  which  and  zero  the  velocity  will  vary 
with  pressure,  diameter,  and  length. 

Assuming  a  maximum  effective  pressure  of  60  pounds 
per  square  inch  in  the  mains,  equal  to  75  pounds 
absolute  or  5  atmospheres,  the  water  discharge  in  a 
six-inch  pipe  100  feet  long  will  be,  per  second  :  cubic 

feet  =  0.0762-/65x^xM1  =  7.85  cubic  feet,  and  7.85  X 
100 

I/  1700  x  |/5  =  7.85  x  41.3  x  2.24=726  cubic  feet, 
and  726  -5-  0.2  x  5  =  726  =  initial  velocity  of  the  steam 
on  entering  the  pipe. 


174  STREET   RAILWAY   MOTORS. 

If  the  length  of  pipe  were  1000  feet,  the  discharge  and 
the  velocity  would  be  reduced  in  proportion  of  y  M 
or  Z?!L  —  229  feet  per  second. 

3.17 

The  general  formula  for  the  discharge  of  steam  is,  in 
cubic  feet,  per  second,  at  atmospheric  density  : — 

c=  0.0762  j/d«  x  y  5  x  41.3  x  -[/p  ;  or  c  =  3 1 .47 
I/  d5  x  V  5  X  j/  p,  in  which  d  =  diameter  in  inches. 

H  =  head,  in  feet  of  water. 

L  =  length  in  feet. 

p  =  density  in  atmospheres. 

If  it  be  found  most  convenient  to  express  the  pressure 
in  pounds,  instead  of  feet  of  water,  the  constant  31.47 
will  become  47.73,  and  H  will  then  represent  pounds 
of  effective  pressure. 

The  following  table,  calculated  from  the  above  for- 
mula, will  facilitate  computations  on  the  capacity  of  mains 
for  the  transmission  of  steam,  and  the  same  table  may 
be  used  for  air  by  multiplying  by  -J/— 6  =  ^  =»  J? 
nearly. 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.      175 


176  STEEET   RAILWAY    MOTORS. 

For  any  other  length  than  one  hundred  feet,  divide 
the  numbers  in  the  table  by  the  square  root  of  the 
length  in  feet,  and  multiply  by  ten. 

For  discharges  at  initial  densities,  divide  the  numbers 
in  the  table  by  the  pressures  in  atmospheres. 

For  initial  velocities,  divide  the  discharge  at  initial 
density  by  area  in  square  feet,  the  quotient  will  give  feet 
per  second. 

Evaporation  of  Water  under  Pressure. 

A  diversity  of  opinion  is  found  to  exist  amongst  prac- 
tical engineers  and  boiler  manufacturers  in  regard  to  the 
effects  of  increased  pressure  upon  evaporation  ;  some  con- 
tending that  the  quantity  of  water  evaporated  under 
high  boiler  pressures  is  greatly  reduced — others  that  the 
difference  is  inconsiderable,  and  others  again  admit  that 
the  question  is  new  to  them  and  has  not  received  atten- 
tion. 

The  fact  of  a  difference  of  evaporation  under  pressure 
is  very  generally  admitted  by  mechanical  engineers,  and 
is  moreover  confirmed  by  direct  experiments  in  England, 
where,  as  the  result  of  28  carefully  conducted  experi- 
ments, it  was  found  that  the  coal  required  to  evaporate 
20  cubic  feet  of  water  at  pressures  from  0  to  60  Ibs. 
above  atmosphere  varied  from  195  to  210  Ibs.,  or  a 
difference  of  8  per  cent  with  3  atmospheres. 

No  explanation  of  this  fact,  so  far  as  the  writer  knows, 
has  been  attempted,  but  it  would  seem  reasonable  to  as- 
sume that  the  consumption  of  coal  should  be  in  propor- 
tion to  the  work  done. 

If  we  suppose  one  cubic  foot  of  water  to  be  confined 


TRANSMISSION  OF  POWER  BY  MEANS  OF  PIPES.       177 

in  a  cylinder  of  one  square  foot  sectional  area  and  of 
indefinite  height,  and  heat  applied  to  convert  the  water 
into  steam  under  the  atmospheric  pressure  of  14.7  pounds, 
the  space  through  which  this  weight  would  move  would 
be  1700  feet,  and  1700x14.7x144=3,598,560  foot- 
pounds of  work  in  the  conversion  of  one  cubic  foot  of 
water  into  steam  under  one  atmosphere  of  pressure. 

Assume  as  a  second  illustration  that  the  pressure  is 
200  Ibs.,  the  temperature  will  be  387  degrees,  and  the 
space  occupied  by  the  steam  tinder  this  pressure  158 
cubic  feet.  The  foot-pounds  of  work  in  the  conversion 
of  the  water  into  steam  under  this  pressure  will  be 
4,550,000,  an  increase  of  951,440  foot-pounds,  or  26  per 
cent. 

The  following  table  of  evaporation  is  based  on  the 
Lockport  duty  of  9  Ibs.  water  to  1  pound  coal  under  25 
Ibs.  pressure,  and  assumes  that  the  consumption  under 
any  other  pressure  is  in  proportion  to  foot-pounds  of 
work. 
Column  1  represents  total  pressure  of  steam, 

"       2         "          temperature. 

"       3         "          cubic  feet  steam  from  1  cubic  foot 
water. 

"       4         "         foot-pounds  of  work  in  expanding. 

u       5         "         pounds  of  water  evaporated  by  1 
Ib.  coal. 


12 


178 


STKEET   RAILWAY   MOTORS. 


1 

2 

3 

4 

5 

14.7 

212° 

1700 

3598560 

9.783 

20 

228 

1281 

3689000 

9.542 

25 

241 

1044 

3759000 

9.364 

30 

252 

883 

3815000 

9.227 

35 

261 

767 

3866000 

9.116 

40 

269 

679 

3911040 

9.000 

45 

276 

610 

3963000 

8.850 

50 

283 

554 

3989000 

8.825 

55 

289 

508  • 

4024000 

8.748 

60 

295 

470 

4061000 

8.668 

65 

301 

437 

4079000 

8.628 

70 

306 

408 

4097000 

8.592 

75 

311 

383 

4115000 

8.553 

80 

316 

362 

4133000 

8.516 

85 

320 

342 

4151000 

8.481 

90 

324 

325 

4169000 

8.444 

95 

328 

310 

4178000 

8.426 

100 

332 

292 

4205000 

8.370 

110 

339 

271 

4293000 

8.201 

120 

341 

251 

4338000 

8.126   . 

130 

352 

233 

4362000 

8.070 

140 

357 

218 

4395000 

8.015 

150 

363 

205 

4428000 

7.950 

175 

376 

178 

4486000 

7.847 

200 

387 

158 

4550000 

7.742 

STEAM  REQUIRED  PER  HORSE-POWER. 

It  is  customary  for  parties  using  power  to  furnish 
other  parties  with  steam  for  a  consideration,  and  the 
charge  made  in  Philadelphia  varies  from  $75  to  $125 
per  horse-power  per  annum. 

This  is  a  very  uncertain  basis  of  charge,  for  the  steam 
consumed  per  horse-power  is  a  very  variable  quantity, 
being  dependent  on  the  degree  of  expansion  in  the 
cylinder. 

If  steam  is  used  at  a  low  pressure  and  without  expan- 
sion, it  requires  fully  one  cubic  foot  of  water  evaporated 


GENERAL   SUMMARY.  179 

per  hour  per  horse-power,  or  0.472  cubic  foot  per  second, 
as  can  be  readily  shown.  Suppose  effective  pressure  = 
20  pounds.  The  foot-pounds  of  effective  work  in 
evaporating  one  cubic  foot  would  raise  144  x  20  =  2880 
pounds  to  a  height  of  767  feet  in  one  hour,  or  36,800 
foot-pounds  per  minute,  which  is  slightly  in  excess  of  a 
horse-power.  At  lower  pressures  a  cubic  foot  of  water 
evaporated  would  produce  less  and  at  higher  pressures 
more,  assuming  that  the  steam  is  used  without  expansion 
in  the  engine  cylinders.  Now,  suppose  steam  to  be  used 
expansively.  In  this  case  half  a  cubic  foot  of  water  per 
hour  would  furnish  a  horse-power,  or  3J  pounds  of  coal. 
At  this  rate  the  margin  of  profit  in  supplying  power 
would  be  very  large  to  a  company  with  numerous 
patrons,  and  at  the  same  time  it  might  prove  quite  eco- 
nomical to  the  consumer.  If  higher  pressures  and 
greater  expansion  could  be  used,  the  economy  would  be 
still  greater. 


XVII. 

GENERAL  SUMMARY. 

THE  fact  that  the  published  reports  of  street  rail- 
way companies  give  but  little  information  by  which 
the  relative  economy  of  the  different  systems  can  be 
compared  is  universally  conceded.  The  reasons  are 
obvious ;  the  reports  of  cost  of  plant  and  of  operation 
are  based  upon  widely  different  conditions.  A  cable  line, 
for  example,  requires  an  expenditure  of  sixty  per  cent, 
of  the  engine  power  at  the  central  station  to  move  the 


180  STREET    RAILWAY    MOTORS. 

cable  alone,  and  this  power  must  be  expended  whether 
there  are  two  or  two  hundred  oars  upon  the  line.  In 
one  case  the  running  expenses  per  car-mile  may  be  ten 
or  twenty  times  as  great  as  in  another.  In  fact,  it  is 
conceded  that  cable  lines  are  adapted  only  to  metropoli- 
tan localities  with  a  heavy  traffic,  and  that  some  other 
system  must  be  used  where  the  travel  is  moderate.  It 
has  been  stated  that  the  average  travel  on  cable  lines  is 
about  six  times  as  great  as  on  those  operated  by  horse  or 
trolley,  but  of  course  no  general  and  invariable  propor- 
tion can  be  established. 

The  only  possible  way  in  which  a  comparison  can  be 
made  of  the  relative  economy  of  different  systems  is  by 
assuming  that  they  are  to  be  operated  under  similar  con- 
ditions, the  most  important  of  which  are,  length  of  line 
operated  and  equal  volumes  of  traffic.  The  assumed 
standard  adopted  has  been  6  miles  of  double  track  and 
the  car  intervals  two  minutes. 

In  estimating  the  cost  of  plant  neither  a  very  high 
nor  a  very  low  estimate  has  been  taken  and  it  must  be 
remembered  that  the  absolute  figures  are  not  of  very 
great  importance  ;  they  affect  chiefly  the  item  of  interest, 
and,  being  the  same  for  all,  do  not  seriously  affect  the 
comparisons  of  operating  expenses. 

Unable  to  procure  desired  information  from  published 
reports  the  author  has  interrogated  officers  of  roads  to 
ascertain  the  engine  power  at  central  station  in  propor- 
tion to  length  of  line  and  volume  of  traffic  and  the  per- 
centage ussd  in  moving  engines,  dynamos,  cables,  motors 
and  in  transmission,  but  in  no  case  has  any  very  satis- 
factory information  been  obtained.  If,  then,  operators 
who  are  familiar  with  any  particular  system,  think  that 


GENERAL   SUMMARY.  181 

they  have  discovered  inaccuracies,  it  is  hoped  that 
due  allowance  will  be  made,  and  they  can  with  their 
superior  knowledge  of  individual  cases  make  such  cor- 
rections as  the  facts  known  to  them  will  warrant.  There 
has  been  no  disposition  to  recommend  any  system  more 
favorably  than  its  merits  deserve,  or  weaken  confidence 
in  any  that  seemed  worthy  of  approval.  To  expose 
errors  where  natural  laws  have  been  violated,  and  where 
failure  and  pecuniary  loss  would  be  inevitable  from  the 
adoption  of  proposed  systems  in  which  such  laws  were 
ignored,  seemed  to  be  simply  a  duty. 

Horse  Cars. — Cars  propelled  by  horse- or  mule-power 
have  presented  the  nearest  approximation  to  uniformity 
in  cost  of  operation,  and  such  uniformity  was  to  be  ex- 
pected. After  eliminating  the  fixed  charges  the  variable 
expenses  of  operation  would  be  nearly  in  proportion  to 
the  number  of  cars  on  the  line ;  in  other  words,  in  pro- 
portion to  the  car-miles ;  while  in  other  systems  de- 
pendent for  power  upon  transmission  by  wires  or  cables 
from  a  central  station,  the  cost  of  power  per  car  will 
vary  between  very  extreme  limits  dependent  upon  the 
number  of  cars  upon  the  line. 

The  variations  in  horse-power  are  chiefly  in  the  item 
of  feed.  The  Chicago  lines  report  cost  of  feed  per 
horse  per  day  18.58  cents.  The  army  rations  for  cavalry 
cost  in  the  east  26  cents.  The  livery  charge  for  feed 
and  stable  service  is  from  60  to  70  cents  per  horse  per 
day.  From  the  sources  of  information  accessible  the 
cost  of  operation  per  car-mile  by  horse-power  has  been 
taken  at  24  cents,  and  an  average  of  5  passengers  to  a 
car  would  be  required  to  pay  expenses. 


182  STREET    RAILWAY    MOTORS. 

Steam  Motors. — The  determination  of  the  consumption 
of  fuel  and  the  cost  of  repairs  in  small  steam  motors 
presented  considerable  difficulty  from  the  fact  that  no 
records  were  accessible  of  the  cost  of  operation  of  such 
motors,  and  the  results  from  performances  of  standard 
locomotives  on  ordinary  roads  are  of  little  value  from 
the  existence  of  widely  different  conditions.  The  trac- 
tion of  cars  on  a  straight  and  level  railroad  is  about  X 
pounds  per  ton  ;  of  a  train  including  locomotive  about 
9  pounds,  but  a  street  motor  has  a  much  worse  track 
and  smaller  wheels,  and  the  traction,  although  not 
readily  determinable  without  direct  experiment,  is  put 
at  not  less  than  25  Ibs.  per  ton  and  the  cars  15  Ibs.  It- 
is  upon  these  resistances  that  calculations  have  been 
based. 

Steam  motors  are  objectionable  on  account  of  smoke, 
ashes,  sparks,  cinders,  and  noise  from  exhaust  and  are 
now  rarely  used. 

Ammonia  Motor. — An  ammonia  motor  invented  and 
patented  by  Dr.  Emile  Lamm  was  operated  in  New 
Orleans  in  1871,  and  reported  upon  favorably  by  a  com- 
mittee of  which  General  G.  T.  Beauregard  was  chair- 
man. 

The  fact  that  ammonia  when  in  a  liquid  state  volatilizes 
at  a  very  low  temperature  and  produces  a  higher  pressure 
at  50°  than  water  at  320°,  led  to  great  expectations  that 
practical  experience  did  not  realize. 

It  was  conceded  by  Dr.  Lamm  that  heat  was  the  real 
source  of  power,  and  that  it  was  impossible  with  a  given 
quantity  of  heat  to  obtain  more  force  with  one  element 
than  with  another.  Comparisons  must  be  made  by 
taking  into  consideration  the  entire  cycle  of  changes,  and 


GENERAL   SUMMARY.  183 

although  fluid  ammonia  would,  in  expansion  into  a 
gaseous  state,  develop  enormous  energy,  yet  in  completing 
the  cycle  of  changes  by  the  reconversion  of  the  gas  into 
a  fluid,  an  amount  of  calorific  energy  was  required  prac- 
tically equal  to  that  which  had  been  expended  in  work 
in  expansion,  and  therefore  no  advantage  was  gained 
over  the  ordinary  steam  engine. 

The  ammonia  motor  was  abandoned  because,  as  General 
Beauregard  says,  "  The  heated  steam  motor"  was  pre- 
ferred "  as  being  cheaper  and  less  troublesome ;"  yet 
after  22  years  the  ammonia  motor  is  now  revived  with 
claims  of  improvements  that  will  render  it  a  practical 
success.  If  so,  experience  in  actual  work  must  demon- 
strate the  fact.  Theory  does  not  offer  m  uch  encouragement 
to  believe  that  a  claim  for  superior  economy  over  any 
other  system  can  be  established. 

The  Hot  Water  Motor. — A  motor  named  the  heated 
steam  motor  was  used  for  some  time  upon  the  street  rail- 
road in  New  Orleans  during  the  presidency  of  General 
Beauregard  and  abandoned  by  a  subsequent  administra- 
tion in  favor  of  mule  power.  The  system  has  recently 
been  revived  under  a  different  name  and  a  company 
formed  to  secure  public  recognition  and  support.  It  was 
recently  brought  to  the  attention  of  and  was  discussed  by 
the  American  Society  of  Civil  Engineers,  but  the  radical 
defect  in  the  system  does  not  appear  to  have  been  recog- 
nized, as  seems  from  the  published  report  of  the  dis- 
cussion held  by  this  very  practical  and  scientific  body. 

The  prominent  feature  in  the  hot  water  system  is  that 
the  water  is  heated  in  a  stationary  tank  to  a  high  tem- 
perature, then  transferred  to  a  boiler  on  the  motor  and 
a  portion  of  the  water,  converted  into  steam  by  reduction 


184  STREET    RAILWAY    MOTORS. 

of  pressure,  is  used  to  move  the  pistons  in  the  motor 
cylinders. 

The  defect  of  the  system,  and  that  which  appears  to 
have  been  overlooked  by  those  who  have  attempted  to 
make  calculations  of  the  length  of  run  based  upon  the 
units  of  sensible  heat  contained  in  the  hot  water,  consists 
in  the  fact  that  for  every  pound  of  water  converted 
into  steam  967  units  become  latent,  and  this  amount  of 
heat  is  taken  from  the  water  that  remains,  thus  cooling  it 
so  rapidly  that,  instead  of  a  run  of  20  miles,  as  some 
have  calculated,  the  motor  would  not  run  two  miles. 

In  consequence  of  this  difficulty  the  hot-water  engine 
must  be  provided  with  a  fire-box  and  fuel  to  generate 
steam  when  the  water  becomes  too  cold  and  the  pressure 
runs  low,  and  it  thus  becomes  an  ordinary  steam  motor 
presenting  no  special  claims  for  public  consideration. 

If,  for  example,  the  motor  should  be  started  with 
water  at  a  temperature  of  356  degrees,  giving  a  pressure 
of  146  pounds  to  the  square  inch,  and  run  until  the 
pressure  should  be  reduced  to  60  pounds,  the  sensible 
temperature  would  become  293  degrees,  a  reduction  of 
only  63° ;  but  in  addition  to  this  every  pound  of  steam 
used  within  the  cylinders  would  have  carried  off  967 
degrees,  approximately,  as  latent  heat  which  is  fifteen 
times  as  much  as  the  thermometric  difference  in  tem- 
perature, and  thus  the  water  in  the  motor  is  cooled  so 
rapidly  that  only  a  very  short  run  is  possible  without 
reheating.  The  failure  to  recognize  this  fact  has  led  to 
errors  in  calculation  that  may  disappoint  expectations 
and  lead  investors  into  serious  financial  losses. 

Gas  Motors. — Theoretically  the  gas  engine  should  con- 
vert into  work  the  greatest  number  of  heat-units  of  the 


GENERAL   SUMMARY.  185 

fuel  consumed  in  its  production.  Instead  of  transmis- 
sion from  a  generator  to  a  motor  cylinder,  which  always 
involves  loss,  the  gas  engine  presents  the  peculiarity  of 
combustion  in  the  cylinder  itself  and  in  direct  contact 
with  the  piston  upon  which  the  energy  is  to  be  expen- 
ded. No  other  mode  of  application  can  secure  a  greater 
number  of  foot-pounds  of  work  in  proportion  to  heat- 
units  developed. 

Practically,  however,  there  is  considerable  diiference 
in  the  cost  of  the  fuel  required,  which  to  a  great  extent 
neutralizes  the  theoretical  advantage.  Naphtha,  which 
is  the  cheapest  fuel  that  can  be  used  in  gas  engines, 
costs  five  times  as  much  per  pound  as  the  cheap  coals 
that  can  be  burned  under  stationary  boilers,  but  can 
utilize  twice  as  many  units  per  pound.  Fuel  is  not  the 
most  expensive  item  in  the  cost  of  operation,  and  there 
seems  to  be  a  possibility  that  gas  motors  may  come  into 
use  to  a  considerable  extent.  They  possess  the  advan- 
tage of  being  independent  motors,  not  subject  to  inter- 
ruption by  derangement  of  central  power  station,  cable, 
or  feed  wires.  On  the  other  hand,  they  present  the 
disadvantage  of  requiring  continuous  operation  with  con- 
sumption of  fuel  when  thrown  out  of  gear  and  not  run- 
ning. Constant  combustion  of  gas  or  vapor  is  necessary 
to  keep  up  circulation  of  hot  water  to  vaporize  the  naph- 
tha. If  this  is  not  done,  hot  water  must  be  drawn  from 
a  tank  before  the  motor  can  be  started.  As  in  the  case 
of  the  ammonia  motor,  experience  may  develop  defects 
and  the  machines  be  found  to  be  more  troublesome  and 
expensive  than  some  other,  but  it  is  soon  to  be  tested. 
Mr.  Yerkes,  the  President  of  the  West  Chicago  Street 
Railway  Company,  has  ordered  twenty  gas  motors  for 


J86  STREET   RAILWAY   MOTORS. 

use  in  that  city.  In  his  remarks  at  a  recent  annual 
meeting  the  statement  was  made  that  "it  is  the  short 
haul  and  the  people  that  hang  on  to  the  straps  that  pay 
the  dividends."  A  suffering  public  has  paid  dividends 
long  enough  by  hanging  on  to  the  straps,  and  means 
should  be  found  to  compel  companies  to  provide  reason- 
able accommodation. 

In  answer  to  a  question  in  regard  to  the  result  of 
experiments  with  motors,  President  Yerkes  said  that  all 
electrical  and  other  motors  for  use  on  the  outlying  roads 
of  the  system  had  been  discarded,  and  that  the  conclusion 
had  been  reached  that  a  gas  motor,  which  the  company 
is  now  having  manufactured,  is  the  best  thing  in  this 
line  that  the  company  has  experimented  with.  The 
motor  referred  to  is  the  Connelley. 

Pneumatic  and  Compressed  Air  Motors. — More  space 
has  been  given  to  the  consideration  of  this  subject  than 
to  any  of  the  other  forms  of  motors  and  systems  of  ope- 
ration, for  the  reasons  that  it  is  the  one  upon  which,  in 
the  mind  of  the  public,  the  greatest  ignorance  prevails, 
and  the  one  to  the  investigation  of  which  the  writer  has 
devoted  the  greatest  amount  of  time  and  attention. 

The  pneumatic  motor  presents  the  following  advan- 
tages : — 

It  is  the  cheapest  of  all  the  systems  in  cost  of  plant 
and  of  operation. 

It  can  run  on  any  surface,  elevated  or  underground 
tracks,  and  requires  no  trolleys  or  cables,  no  subterra- 
nean or  overhead  constructions. 

The  motors  are  all  independent,  so  that  no  derange- 
ment of  machinery  at  the  central  station  can  affect  the 


GENERAL   SUMMARY.  187 

line.  The  engines  and  compressors  being  in  a  number 
of  units,  repairs  to  one  will  not  affect  the  rest. 

There  are  no  live  feed  wires  to  shock  or  kill  men  or 
horses,  or  by  contact  with  telephone  or  telegraph  wires, 
to  communicate  fires  to  buildings  or  shocks  to  occu- 
pants. 

There  are  no  obstructions  to  the  free  use  of  fire 
apparatus. 

There  are  no  dynamos  to  be  burned  and  disabled 
during  electrical  storms. 

There  are  no  broken  strands  of  cable  to  entangle  grip 
bars  and  cause  wrecks  of  cars  and  accidents  to  street 
vehicles. 

There  is  no  necessity,  as  in  gas  motors,  to  keep  the 
machinery  in  constant  motion. 

There  is  no  loss,  as  in  hot  water,  steam,  or  ammonia, 
by  radiation  or  condensation,  but  the  charge  in  a  motor 
will  remain  until  used. 

There  is  no  serious  loss  by  transmission  of  the  power 
from  a  central  station  even  to  a  distance  of  miles. 

The  speed  is  practically  unlimited  except  by  munici- 
pal restrictions. 

No  paying  space  for  passengers  is  occupied  either  by 
air  reservoirs  or  motor  machinery.  The  reservoirs  are 
under  the  seats  and  the  machinery  under  the  floor. 

There  is  a  surplus  of  power  to  ascend  grades  or 
overcome  extraordinary  resistances  of  brief  duration. 

Extra  cars  can  be  provided  to  any  extent  required 
by  the  exigencies  of  the  service  without  reducing  the 
length  of  the  run,  as  the  trail  cars  can  carry  their  own 
charges  of  air  in  reservoirs  under  the  seats. 

A  street  blockade,  or  detention  from  any  other  cause, 


188  STREET   RAILWAY    MOTORS. 

cannot  reduce  the  capacity  for  propulsion.  No  reser- 
voirs of  fuel  or  water  are  required  in  transit,  and  the 
stored  power  remains  intact  until  used,  however  long 
the  period  of  suspension. 

A  peculiar  feature  of  the  Hardie  motor  not  possessed 
by  any  other,  so  far  as  known,  is  that  in  descending 
grades,  or  whenever  the  motor  cylinders  are  called  into 
use  as  brakes,  they  act  as  air  pumps,  and,  instead  of 
using  air,  pump  back  an  additional  supply  into  the 
reservoirs. 

The  fuel  required  for  a  given  amount  of  propulsive 
energy  in  pneumatic  motors  costs  less  than  one-fourth  as 
much  as  an  equal  amount  in  steam  motors  for  similar 
service,  and  this  cost  is  covered  by  seven  mills  per  car 
mile. 

Five  of  the  Hardie  pneumatic  motors  were  in  active 
daily  use  for  several  months  on  the  Second  Avenue 
street  railroad  in  1879,  and  furnished  the  data  upon 
which  the  computations  in  this  volume  were  based  and 
the  results  determined.  From  such  results,  based  on 
repeated  daily  observation,  there  can  be  no  reason  for 
withholding  confidence. 

The  tests  of  the  motor  constructed  for  the  Second 
Avenue  Elevated  Railroad  in  New  York  were  certified 
to  by  the  chief  engineer  of  the  Manhattan  L  Railroad, 
who  is  now  engineer  of  the  Chicago  and  South  Side 
Railroad  ;  by  the  former  train-master  of  the  Manhattan 
L  Railroad  and  master  mechanic  of  the  Suburban  Tran- 
sit Company  of  New  York,  and  now  superintendent  of 
the  Chicago  and  South  Side  Rapid  Transit  Company, 
and  by  the  foreman-machinist  of  the  locomotive  repair 
shop  of  the  Secoild  Avenue  Elevated  Railroad.  These 


GENERAL   SUMMARY.  189 

certificates  referred  to  the  actual  performance  in  hauling 
the  regular  passenger  trains  upon  the  Second  Avenue 
Railroad  making  twenty-three  station  stops,  and  show 
that  every  requirement  was  fulfilled. 

There  was  also  an  award  of  the  medal  of  superiority 
by  the  judges  of  the  American  Institute  in  1878.  There 
was  also  an  expression  of  entire  confidence  in  the  per- 
formance of  the  machine  by  Messrs.  Burnham,  Parry, 
&  Williams  of  the  Baldwin  Locomotive  Works,  and 
a  still  stronger  statement  from  Charles  T.  Parry,  one 
of  the  firm,  who  considered  the  system  not  only  practical, 
but  particularly  well  adapted  for  use  in  cities  and  towns  ; 
he  enumerated  the  advantages,  and  claimed  superior 
economy  in  cost  of  repairs,  as  there  was  no  excessive 
heat  to  burn  out  certain  parts. 

If  a  system  can  justly  claim  the  possession  of  every 
advantage  that  could  be  considered  desirable,  free  from 
any  conceivable  defect,  and  at  the  same  time  more  eco- 
nomical than  any  other,  why  has  it  not  been  universally 
adopted  ? 

The  answers  have  been  given.  They  will  be  briefly 
repeated. 

The  public  was  not  ready  for  the  adoption  of  the 
system  in  1879.  Presidents  of  horse-railroad  companies 
were  afraid  to  allow  cars  to  run  without  horses  in  front, 
thinking  that  the  horses  in  the  street  would  scare,  cause 
accidents,  and  that  suits  for  damages  would  be  insti- 
tuted. Eiforts  to  induce  them  to  have  experts  make 
examination  of  the  merits  of  the  system  proved  fruitless, 
and  were  abandoned. 

There  was  a  general  misapprehension  in  regard  to  the 
loss  of  power  in  compressing  air,  and  directors  of  com- 


190  STEEET    RAILWAY    MOTORS. 

panics  could  not  be  made  to  understand  that  this  loss 
was  compensated  more  than  fourfold  by  economies  in 
other  directions. 

But  the  principal  difficulty  arose  from  the  fact  that 
the  men  who  formed  the  Pneumatic  Tramway  Com- 
pany were  neither  capitalists  nor  practical  men.  They 
had  secured  a  transfer  of  the  patents  from  the  inventor, 
Robert  Hardie,  for  a  stock  consideration  ;  had  capital- 
ized this  stock  at  one  million  dollars,  divided  amongst 
themselves ;  they  sold  some  shares  to  build  five  motors 
for  street  service;  borrowed  money  to  build  the  elevated 
railway  motor  at  the  Baldwin  shops,  could  not  pay  the 
notes  when  due ;  lost  the  control  of  the  patents,  which 
became  tied  up  in  the  estate  of  a  deceased  creditor,  and 
the  result  was  an  abandonment  of  the  entire  enterprise. 
Hardie  lost  his  patents,  his  stock  became  worthless,  and 
he  accepted  the  position  of  superintendent  of  a  loco- 
motive works,  and  has  been  working  at  a  salary  ever 
since. 

This  explanation  will  perhaps  furnish  reasons  why 
the  best  system  for  either  ordinary  or  rapid  transit  in 
cities  has  never  been  adopted  on  a  practical  scale  in  the 
United  States,  although  an  inferior  pneumatic  motor, 
the  Mekarski,  has  been  for  many  years  in  successful  use 
in  Europe. 

There  can  be  no  patent  either  upon  the  use  of  com- 
pressed air  as  a  motive  power,  or  upon  the  combination 
of  compressed  air  with  a  reheating  apparatus  to  increase 
its  efficacy.  Patents  can  be  granted  only  on  new  me- 
chanical devices  or  combinations  to  utilize  the  energy  of 
the  compressed  air.  The  old  patents  have  about  expired, 
and  even  if  they  possessed  a  sufficient  number  of  years 


GENERAL   SUMMARY.  191 

of  vitality  to  obstruct  progress  in  the  use  of  air  motors, 
they  have  been  superseded  by  new  and  improved  de- 
vices, so  that  parties  using  compressed  air  motors  need 
be  under  no  apprehension  of  trouble  from  litigation  on 
the  part  of  holders  of  the  original  patents. 

The  only  practical  questions  of  importance  are,  can 
we  calculate  with  certainty  the  amount  of  air  that  will  be 
required  at  a  given  pressure  for  a  given  length  of  run, 
and  can  this  air  be  furnished  at  an  estimated  cost  that 
can  be  relied  upon  ? 

The  first  of  these  questions  has  been  settled  by  the 
daily  tests  upon  the  Second  Avenue  Railroad.  It  has 
been  positively  determined  that  300  cubic  feet  of  free 
air  when  compressed  will  suffice  to  run  a  motor  of  the 
dimensions  and  weight  there  used  for  an  average  distance 
of  one  mile.  If  the  round  trip  should  be  12  miles,  the 
reservoir  capacity  must  contain  3600  cubic  feet  of  free 
air  plus  a  sufficient  amount  to  retain  an  effective  work- 
ing pressure  on  the  return.  Consequently,  if  the  cars 
are  to  be  dispatched  at  intervals  of  one  minute  with  a 
run  of  12  miles,  the  compressor  plant  must  have  a  ca- 
pacity of  3600  cubic  feet  of  free  air  per  minute.  If  at 
intervals  of  2  minutes,  1800  cubic  feet;  if  at  intervals 
of  4  minutes,  900  cubic  feet ;  if  at  intervals  of  6  min- 
utes, 600  cubic  feet ;  and  if  at  intervals  of  10  minutes, 
360  cubic  feet  per  minute. 

As  to  the  second  question,  the  Norwalk  Iron  Works 
Company,  the  Ingersoll  Rand  Rock  Drill  Company,  and 
several  others  will  furnish  compressor  plant  at  fixed  and 
reasonable  prices  and  guarantee  performanance,  so  that 
there  can  be  no  reason  to  apprehend  disappointment 
from  under-esti mates  of  the  engine  power  required,  the 


192  STREET   RAILWAY    MOTORS. 

quantity  of  air  compressed  in  a  given  time,  or  the  fuel 
consumed  and  cost  of  compression.  The  extensive  use 
of  compressed  air  for  rock-drilling,  tunnelling,  and  other 
purposes,  has  led,  since  1879,  to  great  improvements  in 
compressors",  and  removed  all  elements  of  uncertainty  in 
regard  to  their  operation. 

A  very  important  observation  may  be  added,  that  if 
it  should  be  considered  desirable  after  a  road  has  been 
some  time  in  operation,  to  increase  the  plant  and  to  run 
the  cars  at  shorter  intervals,  no  difficulties  are  presented. 
The  power  is  supplied,  not  by  a  single  large  boiler  and 
engine,  but  by  a  battery  of  boilers  and  several  engines, 
and  the  compressor  plant  also  consists  of  a  number  of 
units  ;  so  that  if  the  building  is  properly  planned,  addi- 
tions and  extensions  can  be  made  indefinitely  as  the  in- 
crease of  business  may  require. 

Electric  Motors  are  much  better  adapted  to  subur- 
ban service  than  either  cable  or  horse  power,  and  are 
coming  into  almost  universal  use  where  the  volume  of 
travel  is  neither  very  small  nor  extremely  large.  For  a 
moderate  business  they  are  less  expensive  in  installation 
and  cheaper  to  operate  than  cable  lines.  They  can  be 
run,  beyond  the  obstructed  streets  of  populous  cities,  at 
any  rate  of  speed  that  may  be  desired,  and  in  suburban 
localities  have  few  objectionable  features  except  the  hum- 
ming noise  which  frightens  horses. 

In  populous  cities,  narrow  streets  and  crowded  thor- 
oughfares, the  electric  or  trolley  system  is  seriously  ob- 
jectionable. The  posts  and  wires  are  not  only  unsightly, 
but  they  introduce  a  very  serious  impediment  to  the  free 
use  of  fire  apparatus  and  may  thus  cause  wide-spread 
ruin.  Numerous  accidents  from  contact  with  live  feed 


GENERAL   SUMMARY.  193 

wires  have  occurred,  and  contact  with  telephone  and 
telegraph  wires  has  been  the  supposed  cause  of  fires  and 
other  calamities. 

No  electric  system,  except  the  storage  battery,  can 
furnish  independent  motors,  and  consequently  any  de- 
rangement of  the  central  plant,  or  of  the  feed  wires 
affects  the  whole  line. 

Electric  storms  sometimes  disable  dynamos  and  cause 
a  suspension  of  operations  upon  the  line. 

With  all  these  disadvantages  the  use  of  the  trolley  is 
increasing,  and  no  doubt  will  continue  to  increase  unless 
a  better  system  shall  be  substituted  and  give  such  evi- 
dence of  superior  economy  and  efficiency  as  to  inspire 
universal  confidence  and  supersede  others  of  inferior 
merit. 

In  reference  to  the  electric  system  of  the  city  of  Rich- 
mond, an  expert  writes:  "The  first  installation  there, 
on  the  Sprague  System,  was  built  without  regard  to  cost, 
was  the  most  expensive  line  in  this  country  at  the  time, 
and  was  extensively  advertised  as  a  grand  success,  both 
practically  and  commercially.  After  the  failure  of  this 
system  it  was  bought  in  by  other  parties,  and  we  have 
no  information  regarding  the  success  of  the  latter  equip- 
ment, but  we  presume  it  is  equal  to  the  average  electrical 
road.  We  are  well  aware  that  great  improvements  have 
been  made  in  the  electrical  equipment  during  the  last 
few  years,  yet  nevertheless  there  are  contingencies  and 
unlooked-for  expenses  which  make  it  impossible  to  esti- 
mate with  any  certainty  on  the  cost  of  operation  and 
maintenance.  The  wonderful  variation  in  figures  sub- 
mitted by  managers  of  such  systems  attests  this  fact. 
We  are  in  correspondence  with  managers  of  many  elec- 
13 


10  I  STREET    RAILWAY    MOTORS. 

trie  roads  who  appear  quite  as  anxious  to-day  for  au  in- 
dependent motor  as  the  managers  of  horse  systems." 

It  is  said  that  sleet  on  the  feed  wire  and  ice  on  the 
rails  sometimes  break  the  electric  circuit  and  give  trouble. 

The  cable  system  is  adapted  only  to  metropolitan  lines 
with  a  very  heavy  business,  and  such  lines  only  can 
prove  remunerative  under  this  system.  More  power  is 
required  for  the  movement  of  the  cable  than  for  the 
propulsion  of  the  cars.  This  power  must  be  sufficient 
for  the  work  at  the  hours  of  maximum  demands,  and 
when  not  fully  utilized  at  other  times  must  result  in 
waste.  The  cable  must  move  even  if  there  is  but  a 
single  car  upon  the  line,  and  to  economize  power  at 
night,  cable  companies  sometimes  resort  to  horse-power. 

The  cable  system  is  liable  to  derangement  and  block- 
ades from  various  causes,  of  which  the  experience  of 
Philadelphia  during  the  past  winter  has  afforded  almost 
daily  illustrations.  The  central  machinery  may  be  dam- 
aged, the  rope  may  break,  strands  may  become  loose 
and  entangle  the  grip  so  that  it  cannot  be  detached, 
and  serious  collisions  and  damages  have  resulted  from 
this  cause. 

Water  running  into  the  slot,  forming  ice  about  the 
cable  and  sheaves,  adds  to  the  difficulties  of  winter  ope- 
ration. 

Independent  motors  that  consume  just  the  amount  of 
power  required  for  the  work  to  be  done  and  no  more^ 
certainly  possess  great  advantages  over  any  cable  system, 
even  at  the  same  cost  for  plant. 

To  complete  the  examination  of  motors,  so  far  as  they 
are  known  to  have  been  used  or  proposed,  a  brief  de- 


GENERAL   SUMMARY.  195 

scription  will  be  given  of  a  motor  that  the  writer  was 
requested  to  examine  and  give  an  opinion  upon  in  1879. 

The  apparatus  consisted  of  two  cylinders,  each  about 
20  inches  in  diameter  and  3  feet  long,  placed  in  line 
about  4  feet  apart,  and  between  the  two  a  piston  rod 
was  moving  slowly  back  and  forth,  making  about  7 
strokes  per  minute.  The  inventor  and  a  number  of 
capitalists  who  had  advanced  money  for  development 
were  present. 

Around  the  apartment  were  about  20  vertical  cylin- 
ders, probably  10  feet  high  and  30  inches  in  diameter, 
connected  by  pipes  so  as  to  form  a  compressed-air  reser- 
voir of  considerable  capacity.  On  one  of  these  cylin- 
ders was  a  steam  gauge  indicating  250  pounds  pressure, 
and  at  one  end  of  the  row  a  small  one-horse  Baxter 
engine  which  could  be  set  in  motion  by  the  admission 
of  air,  and  which  communicated  rotation  to  a  small 
dynamo  which  operated  an  electric  light. 

The  inventor  explained  that  one  of  the  cylinders  was 
a  water  engine  in  which  motion  was  communicated  to  a 
piston  by  admitting  water  alternately  at  each  end,  and 
when  the  stroke  was  completed  allowing  it  to  escape 
into  a  waste  pipe. 

The  use  of  the  second  cylinder  the  inventor  refused 
to  explain,  declaring  that  it  was  his  secret,  but  the  effect 
was,  he  said,  plainly  visible.  Here  were  all  these  reser- 
voirs filled  with  air  under  a  pressure  at  that  time  of  250 
pounds  to  the  square  inch,  running  an  electric  light  en- 
gine, and,  he  added,  "  Bring  up  one  of  your  air  motors, 
and  I  will  charge  it  with  air  in  one  minute." 

This  was  a  very  transparent  fraud.  The  secret  cylin- 
der, no  doubt,  included  a  smaller  one  in  which  a  piston 


196  STREET    RAILWAY    MOTORS. 

compressed  air  by  direct  action  and  with  an  enormous 
waste  of  power.  The  air  compressed  in  this  manner  to 
300  pounds  per  square  inch  would  not  in  expanding 
furnish  more  than  one-twentieth  of  the  power  expended 
in  compression.  The  time  required  to  fill  the  reservoir 
to  300  pounds  of  pressure  would  have  been  36  hours, 
and  the  quantity  of  water  expended  would  have  been, 
under  an  assumed  effective  pressure  of  30  pounds, 
1,498,000  gallons.  The  time  required  to  pump  enough 
air  to  charge  one  motor  car  would  have  been  47  min- 
utes. 

Of  course  this  motor  was  a  fraud  pure  and  simple, 
but  quite  a  number  of  Wall  Street  capitalists  were  vic- 
timized. One  gentleman  said  that  he  had  advanced  to 
the  development  fund  ten  thousand  dollars;  nothing 
has  since  been  heard  from  it. 

The  Keely  Motor  has  not  recently  exhibited  any  of 
the  usual  periodical  spasmodic  signs  of  vitality.  That 
it  is  possible  to  get  something  out  of  noihing  financially 
is  unquestionably  true,  and  Wall  Street  furnishes  daily 
illustrations  of  the  fact,  but  the  laws  of  nature  are 
immutable  and  cannot  be  varied.  Kinetic  energy  can- 
not be  transmitted  without  loss,  and  no  force  can  be 
practically  utilized  that  has  not  required  an  expenditure 
of  a  greater  force  in  its  production.  The  universal 
source  of  power  is  heat.  Steam  is  merely  an  agent  for 
transmission  of  force  from  coal  to  work.  Cable,  electric, 
and  other  systems  of  mechanical  propulsion  of  cars 
derive  their  power  from  combustion  of  fuel.  Water 
powers  owe  their  origin  to  the  vaporization  by  the  heat 
of  the  sun  and  subsequent  condensation,  and  even 
animal  power  is  maintained  by  a  slow  combustion  in  the 


GENERAL   SUMMARY.  197 

lungs  resulting  in  the  same  gaseous  products  that  are 
evolved  in  more  rapid  combustion  in  a  grate. 

To  claim  the  production  of  a  vibrating,  or  any  other 
power  without  the  expenditure  of  at  least  an  equal 
amount  of  energy  in  some  other  form,  would  be  in  oppo- 
sition to  natural  laws,  and  such  claimants  are  either  igno- 
rant and  self-deceived,  or  they  are  impostors  seeking  to 
deceive  others.  There  can  be  no  mechanical  effect  with- 
out an  adequate  cause,  and  perpetual  motion  and  Keely 
motors  are  possible  only  to  that  Being  who  created  the 
world  from  nothing  and  established  the  laws  that 
govern  the  universe. 


APPENDIX. 


Judson  Low-pressure  Air  Storage  System. — This  is  a 
system  to  which  the  attention  of  the  writer  has  recently 
been  directed.  Its  claims,  as  set  forth  in  a  pamphlet 
issued  by  the  Judson  Pneumatic  Street  Railway  Com- 
pany, are  almost  identical  with  those  of  the  high-pressure 
system  already  fully  described.  The  principal  differ- 
ences consist  in  the  use  of  air  at  a  pressure  of  200  pounds 
to  the  square  inch  instead  of  500  pounds,  and  arrange- 
ments for  replenishing  the  supply  in  transit,  at  intervals 
of  a  mile,  from  reservoirs  under  the  track  connected 
with  the  central,  or  power  station,  by  means  of  a  4-inch 
pipe.  So  far  as  public  accommodation,  safety,  and 
economy  are  concerned,  there  is  practically  no  differ- 
ence between  the  high  and  low-pressure  systems.  Of 
course,  high  pressure  requires  stronger  cylinders  for 
storage  than  low  pressure ;  but  by  increasing  the  thick- 
ness of  metal  the  factor  of  safety  can  remain  the  same, 
and  for  a  given  storage  capacity  the  high  pressure  will 
admit  of  reduced  size  of  reservoirs.  It  is  preferable, 
however,  to  make  the  storage  capacity  as  large  as  pos- 
sible without  encroaching  upon  available  space  for  pas- 
sengers. The  Judson  is  simply  a  modification  of  the 
low-pressure  air  system  described  on  page  138. 

From  the  pamphlet  referred  to,  it  appears  that  the 


200  STREET    RAILWAY    MOTORS. 

claims  of  the  Judson  Company,  on  which  the  operation 
of  the  motors  depends,  are  identical  with  those  of  the 
Hardie  motor  of  1879,  and  consist  of  storage  tanks 
under  the  seats,  reducing  valves  to  reduce  pressure  be- 
fore admission  to  motor  cylinders,  and  a  reheating  ap- 
paratus. 

The  estimate  of  cost  of  plant  and  of  operation  differs 
materially  from  the  estimate  on  the  high-pressure  system 
on  pages  101  and  102,  for  the  reason  that  the  conditions 
and  data  given  as  the  basis  of  calculation  are  very  dis- 
similar. When  similar  conditions  are  assumed,  the  dif- 
ferences disappear. 

The  estimate  of  the  Judson  system  is  made  on  a 
double-track  road  7J  miles  long,  with  100  cars  in  con- 
stant motion,  running  at  an  average  speed  of  8J  miles 
per  hour.  Weight  of  car,  6  tons ;  number  of  passen- 
gers, 50  ;  consumption  of  free  air,  50  cubic  feet  per 
car-ton  per  mile  ;  surplus,  20  per  cent. ;  allowance  of 
air  per  car-mile,  420  cubic  feet ;  for  the  100  cars, 
42,000  cubic  feet  per  mile,  or  6000  cubic  feet  per 
minute  compressed  to  200  pounds  ;  3  sets  of  compres- 
sor plant  of  750  horse-power  each  =  2250  horse- 
power ;  coal  consumption,  2  pounds  per  horse-power, 
or  4500  pounds  per  hour  ;  cost  of  compressor  plant, 
$90,000 ;  time  of  running,  20  hours ;  cost  per  day, 
which  includes  only  coal  and  service  at  station,  $221  ; 
cost  per  car-mile,  with  interest  on  plant,  2  cents ;  daily 
mileage  of  cars,  170  miles;  cost  per  car-mile  for  coal 
and  service,  1T3^-  cents. 

As  the  estimate  for  cost  of  power  in  the  high  pressure 
system  was  4^  cents  (page  142),  it  might  seem,  from 
the  above  statement,  that  the  low-pressure  system  was 


APPENDIX.  201 

superior  in  economy ;  but  the  statement  exhibits  the 
usual  disparity  of  conditions,  and  when  brought  to  a 
standard  of  uniformity  the  differences  disappear. 

Coal,  per  horse-power — Low  pressure,  2  pounds  ;  high  pressure, 

2^  pounds. 
Daily  mileage  of  each  car — Low  pressure,  170  miles  ;  high  pressu/e^ 

96  miles.  I 

The  low-pressure  estimate  of  cost  of  power,  lT3ff  cen^/^ 
included,  as  stated,  only  the  cost  of  coal  and  the  service  s 
at  station.  The  high-pressure  estimate,  on  the  contrary, 
included  also  cost  of  repairs  of  station  plant  and  of  street 
motors ;  in  fact,  every  item  connected  with  power. 
Estimating  only  coal  and  service  in  the  high-pressure 
system,  the  cost  would  be  1.48  cents  per  car-mile  for  a 
run  of  96  miles  per  day ;  and  if  the  average  run  were 
taken,  as  in  the  low-pressure  system,  at  170  miles,  the 
cost  per  car-mile  would  be  reduced,  and  still  more  if  2 
pounds  of  coal  were  allowed  to  a  horse-power  instead  of 
2^  pounds. 

It  is  not  claimed,  however,  that  there  are  any  such 
radical  differences  between  the  high  and  low-pressure 
systems  as  would  result  in  any  considerable  difference 
of  expense.  In  this  regard  the  two  systems  may  be 
considered  as  practically  equal.  The  only  important 
question  is,  Which  is  preferable?  to  use  a  pressure  of 
500  pounds  and  run  a  motor  12  miles  without  re- 
charging, or  to  use  a  low  pressure  that  will  require 
recharging  every  mile?  the  difference  in  cost  of  charg- 
ing the  reservoirs  being,  as  shown  on  page  55,  only  1 
mill  per  car-mile. 


202  STKEET    RAILWAY    MOTORS. 

It  may  be  a  question,  also,  whether  heavy  falls  of 
snow,  or  formation  of  ice  around  or  in  the  feed  nozzles 
between  the  tracks,  might  not  cause  trouble  in  winter 
for  the  low  pressure  system  ;  but  if  it  should,  no  doubt 
a  remedy  could  be  found. 

On  the  whole,  therefore,  the  Judson  system  may  be 
considered  preferable  to  any  other  now  used  or  proposed 
except  the  high  pressure,  which  takes  its  charge  of  air 
for  the  whole  run,  requires  no  intermediate  reservoirs, 
and  no  pipe  for  the  whole  length  of  the  track  for  the 
transmission  of  power.  It  is  only  in  case  the  system 
should  be  extended  to  long  inter-urban  lines  that  pipes 
and  intermediate  reservoirs  would  become  necessary, 
and  to  such  lines  the  high-pressure  system  would  be 
well  adapted. 

Electric  Steam  Motor. — A  very  novel  design  for  a 
street  motor  has  been  brought  to  the  attention  of  the 
writer;  and  as  an  effort  has  been  made  in  this  volume 
to  present  a  notice  of  every  motor  known  to  have  been 
used  or  proposed,  whether  good,  bad,  or  indifferent,  a 
few  lines  will  be  devoted  to  this  unique  candidate  for 
popular  favor. 

In  the  electric  steam  motor  it  is  proposed  to  use  all 
the  apparatus  of  an  ordinary  locomotive  to  generate 
steam  upon  a  motor,  and  then  apply  this  steam  to 
rotate  dynamos,  which,  in  turn,  are  to  communicate 
rotation,  by  means  of  suitable  gearing,  to  the  wheels. 

In  forming  an  opinion  as  to  the  utility  of  such  a  com- 
bination, it  must  be  remembered  that  the  great  source 
of  mechanical  energy  is  heat.  The  heat  is  generated  by 


APPENDIX.  203 

combustion  of  fuel,  and  is  transmitted  and  converted 
into  work  by  the  intervention  of  certain  agencies  and 
mechanical  devices. 

The  efforts  of  inventors  must  naturally  be  directed, 
first,  to  the  generation  of  the  heat,  which  represents 
work,  at  the  lowest  possible  cost ;  and,  second,  its  trans- 
mission and  conversion  into  work  with  the  least  possible 
loss. 

With  stationary  compound  engines  it  is  possible  to 
secure  a  horse-power  with  2  pounds  of  coal,  and  to  run 
an  air  motor  1  mile  at  a  cost  of  7  mills  for  fuel. 

In  a  small  steam  motor  the  consumption  of  coal  is  not 
less  than  6  pounds  per  horse-power,  and  the  cost  per 
mile  run  cannot  be  less  than  2-18¥  cents.  But  this  is  not 
all.  The  electric  steam  motor  does  not  transmit  the 
power  directly  to  the  propelling  machinery,  but  to  in- 
termediate apparatus  in  the  form  of  dynamos,  which,  by 
a  system  of  gearing,  finally  transmit  the  power  gene- 
rated in  the  boiler  to  the  axles  of  the  motor. 

No  machinery  or  agency  that  the  brain  of  man  ever 
has  invented  or  can  invent  will  transmit  energy  to  any 
distance,  great  or  small,  without  loss ;  and,  in  general, 
the  greater  the  number  of  intermediate  agencies,  the 
greater  the  loss. 

It  is  not  possible  to  transmit  power  from  the  cylinders 
of  a  locomotive  through  a  dynamo,  or  other  apparatus, 
without  greater  loss  than  would  be  sustained  by  the 
direct  application  of  the  power  to  propulsion.  The 
only  instance  of  the  increase  of  power  in  transit  is  in 
the  reheating  of  compressed  air  before  admission  to  the 
motor  cylinders ;  but  as  heat  is  the  equivalent  of  work, 


204  STREET    RAILWAY    MOTORS. 

this  fact  does  not  invalidate  the  rule.     The  heat  sup- 
plied is  the  equivalent  of  added  energy  for  work. 

It  does  not  seem  possible,  therefore,  that  any  economy 
can  be  secured  by  the  proposed  electric  steam  system  ; 
while  the  weight,  the  cost  of  plant  and  of  repairs,  and 
especially  the  cost  of  fuel,  must  be  largely  increased. 


INDEX. 


LIR  and  gases,  specific  heat  of, 
9,  10 

calculation  of  loss  of,  in  the 
transmission  through  pipes,  ; 
50,  51 
capacity  of,  for  holding  mois- 1 

ture,  46,  47 

compressed,  as  a  motive  power,  j 
extracts  from  the  report ! 
on,  62 
cost  of,  64 
for  elevated  railroads,102- 

107 
future  possibilities  of,  72, 

73 

general  ignorance  in   re-  : 
gard  to  the  use  of,  99, 
100 
motors,  cost  of  operation 

of  the,  100-111 
objections  to,  44 
operation  of  ordinary  rail- 
roads with,  85,  86 
or  pneumatic  motor,  44- 

60 
power  plant,  the  largest 

in  America,  49 
remarks  on,  148,  144 
superiority  of,  39,146,147 
as  a  motive  power,  44 
why  not  in  general   use, 

107-111 

compression  of,  62,  63 
compressor,  47 
compressors,  71 

improvement/8  in,  49,  192 
conveyance  of,  at  the  Jeddo 

tunnel,  49 
cost  of  heating  the,  per  mile, 

67 
cylinder,  effect  of  rupture  of, 

73 
cylinders,  71 


Air,  discharge  of,  fallacious  rule 

for,  169 
dry  and  saturated,  volume  of, 

65,  66 

economy  of,  45 
expansion  of,  65 
free,  quantity  of,  required  to 

run  a  motor,  191 
friction  of,  153,  154 

in  pipes,  as  determined 
from  the  experiments 
at  the  Mt.  Cenis  tun- 
nel, 165-167 

through  long  pipes,  Weis- 
bach's  formula  for  the, 
168,  169 
frost   from  expansion  of,  97- 

100 
importance    of,   as    a   motive 

power,  45 
Judson   low-pressure    storage 

system,  199-202 
locomotive,      efficiency      and 

economy  of  the,  103,  104 
losses  in  the  transmission  of, 

49 
loss  in,  37 

of  thermal  units  by  heat- 
ing, 92 
motor,     Hardie    compressed, 

tests  of  the,  61-94 
motors,  cost  of  plant  and  of 
operation   of  six   miles 
of    double    track    ope- 
rated by,  136 
low-pressure,  138-140 
misnamed,  111 
other,  111-113 
saving  of  fuel  in,  106 
properties  of,  46 
pumps,  increased  power  from 
motor  cylinders  acting  as, 
68-70 


INDEX. 


Air,  quantity  required  for  running 

a  street  motor,  52,  53 
receivers,  73 
reservoirs,  83 

intermediate,  85 
of,  79 
steam,  and  gas,  friction  of,  in 

long  pipes,  168 
tanks,  modes  of  charging,  94, 

95 

weight  of,  10 

Ammonia,  advantage  of,  19,  21 
and  hot-water  motors,  cost  of 
plant  and  of  operation  by 
the,  36,  37 

engine,  Lamm's,  23,  24 
manuf'acture     of,     for     horse 

cars,  20 
motor,  17-28 

cost  of  plant  and  of  ope- 
ration of  six  miles 
of  double  track  ope- 
rated by  the,  134, 
135 

of  running  the,  25,  26 
Dr.  E.  Lamm's,  19 
remarks  on  the,  142,  143 
revival  of  the,  26-28 
nummary  of  the,  182,  183 
tests  of,  27,  28 

by   General   Beaure- 

gard,  24, 182 
properties  of,  17-19 
reasons  for  the  abandonment 

of,  22,  183 
Ammoniacal  gas,  liquefaction  of, 

23 
special  qualities  of, 

20 

subdivision  of,  20 
Angomar  motor,  28 
Atmospheric  railway,  the,  112 


pATTERIES,  storage,  140-147 
JD    Beaumont  locomotive,  52,  53 
Beaumont's  tests,   discussion    of, 

60 
with   high   pressures,  58, 

59 

Beauregard,  General,  reasons   for 
the  abandonment  of  am- 
monia given  by,  22,  183 
tests  of  the  ammonia  mo- 
tor by,  24,  182 


Boston,  West  End   Company  of, 

earnings   and   expenses  of  the, 

5,  6,  118,  131 
Box,   Thomas,   table    of,   for   the 

friction  of  air,  steam,  and  gas 

in  long  pipes,  168 


nABLE  and  electric  roads,  113- 
\J        127 

average  horse-power   to   1000 

feet  of,  123 

cost  of  plant  and  of  operation 
of  six  miles  of  double  track 
operated  by,  137 
lines,  loss  in,  37 

objection  to,  139 
remarks  on,  145,  146 
travel  on,  180 
roads,  estimate  of  cost  of,  123- 

127 
expenses  per  car-mile  on, 

118 
operating  statistics  of,116, 

117,118 

system,  summary  of  the,  194 
Carbon ,  evaporation  of  water  from , 

10 

oxygen  required  for  the  com- 
bustion of,  10 
Carbonic  acid,  cost  of,  as  a  motive 

power,  147-149 
density  of,  148 
motor,  139,  140 
I  Car  expenses,  total,  3 

horse-power  at  axles  required 

to  propel  a,  128 
-mile,    cost    of    horse- power 

per,  3 
expenses    per,   for    horse 

roads,  6,  7 
I  Cars,  cost  of,  2 

traction  of,  182 
i  Cast-iron,  specific  heat  of,  9 
i  Centigrade  thermometer,  the,  9 
Chapin     mines,     Michigan,    com- 
pressed air  power  plant  at  the, 
49 
Chicago  City  Railway,  expenses  of 

the,  6 

Coal  consumed  per  ton-mile  in  or- 
dinary passenger  trains,  14 
consumption   of,   by  locomo- 
tives, 11 
by  steam  motors,  14 


INDEX. 


207 


Coal,  units  of  heat  yielded  by,  10 
Cold  and  heat  by  compression  and 

expansion,  70-72 

Combustion  of  carbon,  oxygen  re- 
quired lor  the, 10 
Compressed    air    and    pneumatic 
motors,  summary   of,  186- 

192 
air  motors,  cost  of  operation 

of  the,  100-111 

air  motors,  cost  of  plant  and 

of  operation  of  six  miles  of 

double  track   operated  by, 

136 

air  or   pneumatic  motor,  44- 

60 

remarks  on,  143-145 
superiority  of,  146,  147 
why  it  is  not  in  general 

use,  107-111 

Compression,  adiabatic,  47,  48 
and  expansion,  heat  and  cold 

by,  70-72 

economical  modes  of,  94-100 
high,    determination    of    the 

actual  loss  in,  54,  55 
horse-powers  required  for.  95, 

96 

isothermal,  47 
Compressor  plant,  cost  of,  107 

plants,  location  of,  85 
Compressors,  expense  of  running, 

97 
Connelly  gas  motor,  39-41 

cost  of  fuel  for  the, 43, 

44 
of    operation    of 

the,  41 

forms  of  the,  41,  42 
Cost,  estimates  of,  121 
Crosby  &  Hall,  summary  of  ex- 
penses for  an    electric   railway 
given  by,  130 

Cylinders,   motor,   acting  as  air- 
motor  pumps,  increased 
power  from,  fi8-70 
arrangement  of,  68,  69 
power  of,  73-76 


I) 


AVIS,  CHARLES  H.,  data  in 

reference  to  street  railways 

in  Massachusetts  by,  4,  5 

facts  and  figures  in  regard  to 

electric  roads  by,  119,  120 


EAST     CLEVELAND     Electric 
Road,  128,  129 

Electric  and  cable  roads,  113-127 
line,  cost  of  operation  of  six 
miles  of  double  track,  132, 
133 
lines,  127-137 

cost  of  plant  and  of  ope- 
ration of  six  miles  of 
double  track  operated 
by, 1ST 

objection  to,  139 
remarks  on,  145 
motors,  summary  of,  192-194 
railroads  and  equipments,  cost 
of  items  entering  into   the 
construction  of,  129,  130 
railway,  estimate  of  cost  per 

car-mile  of,  131,  132 
road,  cost  of  plant  of  a,  119 
investment  and  operating 

expenses  of  a,  119 
roads,  expenses  per  car-mile 

on,  118 
ope  rating  statistics  of,  116, 

117,118,119,120 
steam  motor,  202-204 
traction  efficiency,  129 
Electricity,  loss  of,  37 
Engine,  Lamm's  ammonia,  23,  24 
Engines,  cost  of,  15 

gas,  the  principle  of  all,  40 

thermal  units  utilized  in,  38 
Evaporation  of  water  under  pres- 
sure, 176-178 
table  of,  177, 178 
Expansion  and  compression,  heat 

and  cold  by,  70-72 
of  air,  frost  from,  97-100 


FAHRENHEIT       thermometer, 
the,  9 

Fluids,  discharge  of,  through  ori- 
fices, 151-153 

elastic,  and  water,  the  law 
which  defines  the  rela- 
tions between,  150 
demonstration  of  the  law 
of  the  discharge  of, 
through  long  pipes,  157- 
165 

density  as  an  element  in 
determining  the  resist- 
ance of,  156 


208 


INDEX. 


Fluids,  elastic,  peculiarity  in  using 

tables  for  the  friction  of, 

through  long  pipes,  155, 

15(3 

resistance  of  long  pipes  to 

the  flow  of,  153-156 
Friction,  formula  for  calculating 
tables  of  loss  of  head   by, 
170,  171 

loss  of  power  due  to,  84 
of  air,  steam,  and  gas  in  long 
pipes,  table  of  T.  Box 
for  the,  168 

through  long  pipes,  Weis- 
bach's  formula  for  the, 
168,  169 

of  elastic  fluids  through  pipes, 
peculiarity  in  using  tables 
for,  155,  156 

table  of  loss  by,  for  steam,  172 
Frost  from  expansion  of  air,  97- 
100 


G 


AS,  am  moniacal,  liquefaction  of, 


special  qualities  of,  20 
engines,  the  principle  of  all,  40 
thermal  units  utilized  in, 

38 
motor,  Connelly,  39-41 

cost  of  fuel  for  the, 

43,  44 
of    operation    of 

the,  41 

forms  of  the,  41,  42 
motors,  37-44 

advantages  and  disadvan- 

tages of,  185 

cost  of  plant  and  opera- 
tion   of    six    miles    of 
double   track  operated 
by,  135,  136 
development  of,  39 
probable  difficulties  in  the 

use  of,  42,  43 
remarks  on,  144,  145 
summary  of,  184-186 
steam,  and  air,  friction  of,  in 

long  pipes,  168 
Gases  and  air,  specific  heat  of,  9, 

10 
Grades,  76,  77 

overcome  and  loads  carried  by 
the  pneumatic  motor,  73-76 


HARDIE  compressed  air  motor, 
tests  of  the,  61-94 
motor,  52,  53 

consumption  of  free  dry 

air  in  the,  14 
horse-power  of  the,  80,  81 
location    of     the    power 

plant  for  the,  83-86 
objections  to  the,  81,  82 
observations   on  tests  of 

the,  89-94 
peculiar    feature   of    the, 

188 
points  in  favor  of  the,  80, 

81 

reasons  for  failure  of  adop- 
tion of  the,  189,  190 
record  of   direct    experi- 
ments with  the,  86-89 
report  of  the  test  of  the, 
on    the    elevated    rail- 
road, 103-106 
test  of  the,  188,  189 
Robert,  causes  of  failure  in  the 
introduction    of   pneu- 
matic motors  given  by, 
108-110 

motors  designed  by,  61 
Hardie's  tests  with  high  pressures, 

57,  58 
Heat  and  cold  by  compression  and 

expansion,  70-72 

latent,  of  steam,  29 

of  water,  8 

pressures,  volumes,  and 
thermal  units,  table  of, 
30,  31 

liberation  of,  47,  48 
specific,  definition  of,  9 
of  air,  46 

and  gases,  9,  10 
of  cast  iron,  9 
of  ice, 9 
of  steam,  10,  30 
units  of,  yielded  by  coal,  10 
Hill,  E.,  on  charging  air  tanks, 

94,95 
on    frost    from   expansion   of- 

air,  97-99 
Horse-car,  ordinary  weight  of  the, 

77 

Horse- cars,  manufacture  of   am- 
monia for,  20 
ordinary,  traction  of,  78 
summary  of,  181 


INDEX. 


209 


Horse,  cost  of  feed,  per,  per  day, 

181 

of  one,  one  month,  4 
Horse-power  at  axles  required  to 

propel  a  car,  128 
charge  per,  in  Phila- 
delphia, 178 
con  s  u  m  pti  on  of  steam 
by  locomotives  per, 
12 

cost  of,  one  year,  2,  3 

determination  of  the, 

required  to  propel 

an  ordinary  street 

motor,  12 

of  the  Hardie  motor, 

80,81 

remarks  on,  143 
steam    required    for, 

178, 179 

the  usual  unit  of,  128 
Horse-powers   required    for  com- 
pression, 95,  96 

Horse  railroad,  cost  of  plant  and 
of  operation   for  six   miles 
double  track,  133 
railroads,  cost  of  power  on, 

119 
estimate  of  cost  of,  122,  j 

123 

railways,  1-7 

Horses  and   steam    motors,  com- 
parative cost  of,  13,  14 
Hot-water  and  ammonia  motors, 
cost  of   plant   and    of 
operation    by  the,    36, 
37 
motor,  28-37,  143 

comparison   of,   with 
other    motors,    35, 
36 
cost  of  operation  with  j 

the,  135 
summary  of  the,  183, 

184 
system,  defect  of  the, 

184 

tests  of  a,  33,  34 
Hydraulic  pipes,  cost  of,  51 


ICE,  melting-point  of,  8 
specific  heat  of,  9 
Iron,  cast,  specific  heat  of,  9 


JEDDO    tunnel,   conveyance    of 
air  at  the,  49 

Judson   low-pressure   air  storage 
system,  199-203 

T7EELEY  motor,  the,  196,  197 

LAMM,  Dr.  E.,  ammonia  motor 
of,  19 
invention  of  the  ammonia 

motor  by,  182 

Lamm's  ammonia  engine,  23,  24 
Law,  fundamental,  for  all  steam 

transmission,  157, 158 
of   the    discharge    of   elastic 
fluids  through   long  pipes, 
demonstration  of  the,  157- 
165 

the,  which  defines  the   rela- 
tions between  water  and  any 
elastic  fluid,  150 
Locomotive,    air,    efficiency    and 

economy  of  the,  103,  104 
Beaumont,  52,  53 
fireless,  28 

inappropriateness  of   the 

term,  34,  35 

New  Orleans  fireless,  descrip- 
tion of  the,  32,  33 
thermal  units   utilized   in   a, 

38 
Locomotives,  consumption  of  coal 

by,  11 

of  steam  by,  11 
evaporation  of  water  by,  11 
steam,  coal   consumption  in, 

106 
Low-pressure  air  motors,  138-140 


MAINS,  capacity  of,  and  velocity 
of  steam,  173,  174 
Massachusetts,  data  in   reference 

to  street  railways  in,  4,  5 
Mekarski  motor,  52,  53 
Motor,  adhesion  with  a  small,  74, 

75 
ammonia,  17-28 

cost  of  plant  and  opera- 
tion of  six  miles  of 
double  track  operated 
by  the,  134,  135 


14 


210 


INDEX. 


Motor,  ammonia,  cost  of  running 

the,  25,  26 

remarks  on  the,  142,  143 
revival  of  the,  26-28 
summary  of  the,  182, 183 
tests  of,  27,  28 

by  Gen.  Beau  regard, 

24 

a  new,  113 
Angomar,  28 
carbonic-acid,  139,  140 
Connelly  gas,  39-41 

cost  of  fuel  for  the, 

43,44- 
of    operation    of 

the,  41 

forms  of  the,  41,  42 
cylinders  acting  as  air-pumps, 
increased  power  from,  j 
68-70 

arrangement  of,  68,  69 
power  of,  73-76 
derailment  of  a,  79,  80 
description  of  a,  195, 196 
electric  steam,  202-204 
Hardie,  52,  53 

compressed    air,    test    of 

the,  61-94 
consumption  of  free  dry 

air  in  the,  14 
horse-power  of   the,    80, 

81 

location    of    the    power- 
plant  for  the,  83-86 
objections  to  the,  81,  82 
observations  on   tests   of 

the,  89-94 
peculiar  feature   of   the, 

188 
points    in    favor  of   the, 

80,81 

reasons  for  failure  of  adop- 
tion of  the, 189,  190 
record   of    direct  experi- 
ments with  the,  86-89 
report  of  the  test  of  the, 
on    the    elevated    rail- 
road, 103-106 
test  of  the,  188, 189 
hot-water,  28-37,  143 

comparison  of,  with  other 

motors,  35,  36 
cost  of  operation  with  the, 

135 
summary  of  the,  183,  184 


Motor,  hot- water  system,  defect  of, 

the, 184 

tests  of  a,  33,  34 
Keely,  196,  197 
Mekarski,  52,  53 
perfect,  conditions  required  in 

a,  141 

pneumatic,    actual    perform- 
ance of  the,  68 
advantages   of   the,   186- 

188 

application  of  the,  to  ele- 
vated railroads,  79 
cost  of  plant  and  of  opera- 
tion for  the,  101,  102 
grades  overcome  and  loads 

carried  by  the,  73-76 
miles  run  by  the,  67,  68 
or  compressed  air,  44-60 
power  of  the,  with  a  full 

cylinder  of  air,  77 
quantity  of  air  required   for 

running  a,  52,  53 
of  free  air  required  to  run 

a,  191 

Scott-Moncrieff,  53 
street,  traction  of  a,  75,  76 
Motors,  air,  misnamed,  111 
others,  111-113 
saving  of  fuel  in,  106 
ammonia  and  hot-water,  cost 
of  plant  and  of  operation  by 
the,  36,  37 

comparison  of,  141,  142 
compressed  air,  cost  of  opera- 
tion of  the,  100-111 
compressed  air,  cost  of  plant 
and  of  operation  of  six  miles 
of  double  track  operated  by, 
136 

depreciation  of,  15 
electric,  summary  of,  192-194 
gas,  37-44 

advantages  and  disadvan- 
tages of,  185 
cost  of  plant  and  opera- 
tion   of    six    miles    of 
double  track   operated 
by,  135,  136 
development  of,  39 
probable  difficulties  in  the 

use  of,  42,  43 
remarks  on,  145 
summary  of,  184-186 
low-pressure  air,  138-140 


INDEX. 


211 


Motors,  Mr.  Yerkes  on  the  result 

of  experiments  with,  186 
pneumatic    and     compressed 
air,   summary  of,  186- 
192 

causes  of  failure  in  the 
introduction  of,  108- 
110 

repair  of,  15 

small,  of  5  tons,  with  cars  at- 
tached, 77-80 
steam,  8-17 
cost  of,  13 

of  operation  with,  17 
of  plant  and  of  opera- 
tion of  six  miles  of 
double  track  oper- 
ated by, 134 
objection  to,  182 
plant  required  for,  16,  17 
summary  of,  182 
street,  power  required  to  pro- 
pel, by  compressed  air,  12 


NAPHTHA,    advantages    of   as 
fuel,  38 
cost  of,  38 
Napier,   R.    D.,    experiments    on 

steam  by,  152 
New  Orleans  flreless  locomotive, 

description  of  the,  32,  33 
New  York,  expenses  of  horse-car 

companies  in,  4 
New  York,  Second  Ave.  Railroad, 

air-compressors    used    on    the, 

47 
New  York,  Second  Ave.  Railroad, 

cost  of  plant  of,  1,  2 
New  York,  Second  Ave.  Railroad, 

expenses  of  operation  of,  2-4 
Now  York,  Second  Ave.  Railroad, 

number  of  passengers  carried  on 

the,  3,  4 


OPERATION,  expenses  of,  2-4    ! 
Oxygen  required  for  the  com-  j 
bustion  of  carbon,  10 


PARIS,  use  of  air  in,  49,  50 
Passenger,  cost  per,  carried,  4 
Philadelphia,  charge  in,  per  horse- 
power of  steam,  178 


Pipes,  friction  of  air  in,  as  deter- 
mined from  the  experiments 
at  the  Mt.  Cenis  Tunnel, 
165-167 

hydraulic,  cost  of,  51 
long,    demonstration    of   the 
law  of  the  discharge  of 
elastic  fluids   through, 
157-165 

friction  of  air,  steam,  and 
gas  in,  table  of  T.  Box 
for  the,  168 

friction   of   air    through, 
Weisbach's  formula  for 
the,  168,  169 
resistance  of,  to  the  flow  of 

elastic  fluids,  153-156 
of  equivalent  resistances,  169, 

170 

peculiarity  in  using,  tables  for 
the  friction  of  elastic  fluids 
through,  155,  156 
transmission     of     power    by 

means  of,  149-179 
Plant,  cost  of.  1,  2 
Pneumatic    and    compressed    air 
motors,   summary  of,   186- 
192 
motor,  actual  performance  of 

the,  68 

advantages  of  the, 186-188 
application  of  the,  to  ele- 
vated railroads,  79 
cost  of  plant  and  of  opera- 
tion for  the,  101,  102 
grades  overcome  and  loads 

carried  by  the,  73-76 
miles  run  by  the,  67,  68 
motors,  causes   of  failure  in 
the  introduction  of,  108-110 
or  compressed  air  motor,  44- 

60 
Tramway  Engine  Co.,  tests  by 

the,  61 
Potter,  Charles  W.,  on  losses,  in 

compression  of  air,  56 
report  of,  on  the  test  of 
the  Hardie  motor  on  the 
elevated  railroad,.  103- 
106 
Power,  cost  of,  on  horse  railroads, 

119 
losses  in  the  transmission  of, 

37,  38 
loss  of,  due  to  friction,  84 


212 


INDEX. 


Power,   motive,  cost  of  carbonic  i 

acid  as  a,  147-149 
plant,  location  of  the,  83-86 
transmission  of,  by  means  of 

pipes,  149-179 
Pressure,    evaporation    of    water 

under,  176-178 
high,  economy  of,  56 
utilization  of,  54 
Pressures,  absolute,  table  of,  29 
high,  Beaumont's  tests  with, 

58,  59 
Hardie's   tests    with,   57, 

58 
table  of  experimental  data  of, 

59 

volumes,  thermal  units,  and 
latent  heat,  table  of,  30, 
81 


"DAILROAD      trains,    ordinary, 
it    traction  of,  75 
Railroads,  elevated,  application  of 
the  pneumatic  motor  to, 
79 
compressed    air  for    the, 

102-107 
ordinary,   operation   of,   with 

compressed  air,  85,  86 
traction  on,  85 
street,  traction  on,  85 
Railway,  atmospheric,  the,  112. 
Railways,  horse,  1-7 

street,  statistics  of,  117,  118 
Ramsay,  M.,   operating  statistics 
of  cable  and  electric  roads  by, 
115-117 

Reading  Railroad,  water  per  ton- 
mile  used  by  the,  11 
Reducing  valve,  66 
Reynolds,  G.  H.,  observations  of, 

on  compressed  air,  47 
Richmond,  electric  system  of  the 

city  of,  193,  194 
Rides,  number  of,  per  capita  of 

population,  5 
Roads,   cable    and    electric,   113- 

127 
operating     statistics     of, 

116,  117, 118 
electric,    operating    statistics 

of,  116, 117,  118,  119,120 
Rochester,  earnings  of  horse  rail- 
ways in,  5 


SAN   FRANCISCO,  use  of  low- 
pressure  air  motors  in,  138 
Scott-Moncrieff  motor,  53 
Specific  heat,  definition  of,  9 

of  air  and  gases,  9, 10 
of  cast-iron,  9 
of  ice,  9 
of  steam,  10 
Statistics  of  street  railways,  117, 

118 
of  30  roads  operated  by  animal 

power,  5 
operating,  of  cable  and  electric 

roads,^116,  120 
Steam,  advantage  of  ammonia  as 

a  substitute  for,  21 
charge   in    Philadelphia,   per 

horse-power  of,  178 
consumption   of,   by  locomo- 
tives, 12 
density  of,  8 
gas,  and  air,   friction   of,   in 

long  pipes,  168 
latent  heat  of,  29 
locomotives,    coal    consump- 
tion in,  106 
losses  of,  11 
loss  of,  37 

motor,  electric,  202-204 
motors,  8-17 

and   horses,   comparative 

cost  of,  13 
consumption  of  coal  by. 

14 
cost  of,  13 

of  operation  with,  17 
of  plant  and  of  ope- 
ration of  six  miles 
of  double  track  ope- 
rated by, 134 
objection  to,  182 
plant  required  for,  16, 17 
summary  of,  182 
required  for  horse-power,  178, 

179 

specific  heat  of,  10,  30 
table  of  discharge  of,  167,  175 
of  loss  by  friction  for,  172 
thermal  units  in  one  pound  of, 

29 

required  for  the  con- 
version of  water 
into,  11 

transmission,        fundamental 
law  for  all,  157,  158 


INDEX. 


213 


Steam,  velocity  of,  151-153 

capacity    of   mains,   173, 

174 

volume  of,  11,  30 
weight  of,  8,151-153 
Storage  batteries,  140-147 
Street  railways  in  Massachusetts, 
data    in    reference    to, 
4,  5 

statistics  of,  117,  118 
Suction  valves,  68 
Sulphuric  acid,  cost  of,  147 
Summary,  general,  179-197 


rpABLE   of    absolute    pressures, 
1        29 

of  discharge   of   steam,    167, 

175 

of  evaporation,  177,  178 
of  loss  by  friction  for  steam, 

172 

of  pressures,  volumes,  thermal 
units,  and  latent  heat,  30, 
31 

of  the  horse-power  at  axles 
required    to  propel   a  car, 
128 
Temperature,    increase    of,    with 

adiabatic  compression,  48,  49 
Thermometer,  centigrade,  9 

Fahrenheit,  9 
Track,  cost  of,  per  mile,  1 

expenses,  3 
Transmission  of  power,  losses  in, 

37,  38 

Trolley,  objections  to  the,  140, 141, 
192,  193 


UNITED  STATES  census,  statis- 
tics of  street  railways  from  the, 
117,  118 

Units,  thermal,  in  one  pound  of 
steam,  29 


Units,  thermal,  loss  of,  by  heating 

air,  92 
pressures,  volumes,  and 

latent    heat,    table  of, 

30,  31 
utilized  in  gas  engines  and 

in  a  locomotive,  38 


VALVE,  reducing,  66 
V     suction,  68 

Volumes,  pressures,  thermal  units, 
and  latent  heat,  table  of,  30,  31 


WATER  and  elastic  fluids,  the 
law  which  defines  the  rela- 
tions between,  150 
boiling-point  of,  8,  9,  28 
composition  of,  8 
density  of,  8 

evaporation    of,    by    locomo- 
tives, 11 
from  carbon,  10 
under  pressure,  176-178 
expansion  of,  in  freezing,  8 
latent  heat  of,  8 
tanks,  71 

thermal  units  required  for  the 
conversion  of,  into  steam,  11 
Weisbach's  formula  for  the  fric- 
tion of  air  through  long  pipes, 
168,  169 
Wellington  on  the  consumption  of 

steam  per  horse-power,  12 
West  End  Railway  Co.,  of  Boston, 
earnings  and  expenses  of  the, 
5,  6,  118,  131 
Windsor,  H.  H.,  on  statistics   of 

horse  railway  companies,  6 
Wire  drawing,  loss  by,  56 


1 


Mr.,   on  the  result  of 
experiments  with  motors,  186 


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AMATEUR  MECHANICS'  WORKSHOP: 

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ARMSTRONG.— The  Construction  and  Management  of  Steam 

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BARLOW.— The    History    and    Principles    of   Weaving,   by 

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BIRD. — The  American  Practical  Dyers'  Companion: 

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BLINN. — A  Practical  Workshop  Companion  for  Tin,  Sheet- 
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Tin,  Sheet-Iron  and  Copper-plate  Workers;  Practical  Geometry; 
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Metals,  Lead-pipe,  etc.;  Tables  of  Areas  and  Circumference* 
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etc.  By  LEROY  J.  BLINN,  Master  Mechanic.  With  One  Hundred 
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BOOTH.— Marble  Worker's  Manual: 

Containing  Practical  Information  respecting  Marbles  in  general,  theit 
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Secrets,  etc.,  etc.  Translated  from  the  French  by  M.  L.  BOOTH, 
With  an  Appendix  concerning  American  Marbles.  I2mo.,  cloth  $1.50 
BOOTH  and  MORFIT.— The  Encyclopaedia  of  Chemistry, 

Practical  and  Theoretical : 

Embracing  its  application  to  the  Arts,  Metallurgy,  Mineralogy, 
Geology,  Medicine  and  Pharmacy.  By  JAMES  C.  BOOTH,  Melter 
and  Refiner  in  the  United  States  Mint,  Professor  of  Applied  Chem- 
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BRAMWELL.— The  Wool  Carder's  Vade-Mecum* 

A  Complete  Manual  of  the  Art  of  Carding  Textile  Fabrics.  By  W» 
C.  BRAMWELL.  Third  Edition,  revised  and  enlarged.  Illustrated. 
Pp.  400.  I2mo $2.50 

BRANNT.— A   Practical   Treatise  on  Animal  and  Vegetable 

Fats  and  Oils : 

Comprising  both  Fixed  and  Volatile  Oils,  their  Physical  and  Chemi- 
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BRANNT. — A  Practical  Treatise  on  the  Manufacture  of  Soap 

and  Candles : 

Based  upon  the  most  Recent  Experiences  in  the  Practice  and  Science ; 
comprising  the  Chemistry,  Raw  Materials,  Machinery,  and  Utensils 
and  Various  Processes  of  Manufacture,  including  a  great  variety  of 
formulas.  Edited  chiefly  from  the  German  of  Dr.  C.  Deite,  A. 
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Illustrated  by  163  engravings.  677  pages.  8vo.  .  .  $7.50 

BRANNT.— A  Practical  Treatise  on  the  Raw  Materials  and  the 
Distillation  and  Rectification  of  Alcohol,  and  the  Prepara- 
tion of  Alcoholic  Liquors,  Liqueurs,  Cordials,  Bitters,  etc.  : 
Edited  chiefly  from  the  German  oi  Dr.  K.  Stammer,  l)r.  F.  Eisner, 
and  E.  Schubert.     By  WM.  T.  BRANNT.     Illustrated  by  thirty-one 
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BRANNT— WAHL.— The  Techno-Chemical  Receipt  Book: 

Containing  several  thousand  Receipts  covering  the  latest,  most  «« 
portant,  and  most  useful  discoveries  in  Chemical  Technology,  antf 
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Gearing,  Presses,  Horology  and  Miscellaneous  Machinery ;  and  in- 
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BOWMAN.— The  Structure  of  the  Wool  Fibre  in  Its  Relation 
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•  Being  the  substance,  with  additions,  of  Five  Lectures,  deliverea  at 
the  request  of  the  Council,  to  the  members  of  the  Bradford  Technical 
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BYRNE.— Hand-Book  for  the  Artisan,  Mechanic,  and  Engi- 
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BYRNE. — Pocket-Book  for  Railroad  and  Civil  Engineers: 

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BYRNE.— The  Practical  Metal- Worker's  Assistant :  f 

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and  Alloys;  Forging  of  Iron  and  Steel;  Hardening  and  Tempering; 
Melting  and  Mixing;  Casting  and  Founding  ;  Works  in  Sheet  Metal; 
the  Processes  Dependent  on  the  Ductility  of  the  Metals;  Soldering; 
and  the  most  Improved  Processes  and  Tools  employed  by  Metal- 
workers. With  the  Application  of  the  Art  of  Electro-Metallurgy  to 
Manufacturing  Processes ;  collected  from  Original  Sources,  and  from 
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BYRNE.— The  Practical  Model  Calculator: 

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CABINET  MAKER'S  ALBUM  OF  FURNITURE: 
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Oblong,  8vo $2.00 

CALLINGHAM.— Sign  Writing  and  Glass  Embossing: 

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CAMPIN. — A  Practical  Treatise  on  Mechanical  Engineering: 
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shop  Machinery,  Mechanical  Manipulation,  Manufacture  of  Steam- 
Engines,  etc.  With  an  Appendix  on  the  Analysis  of  Iron  and  Iron 
Ores.  By  FFANCIS  CAMPIN,  C.  E.  To  which  are  added,  Observations 
on  the  Construction  of  Steam  Boilers,  and  Remarks  upon  Furnaces 
used  for  Smoke  Prevention ;  with  a  Chapter  on  Explosions.  By  R. 
ARMSTRONG,  C.  E.,  and  JOHN  BOURNE.  Rules  for  Calculating  th« 
Change  Wheels  for  Screws  on  a  Turning  Lathe,  and  for  a  WheeU 
cutting  Machine.  By  J.  LA  NICCA.  Management  of  Steel,  Includ<- 
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CAREY.— A  Memoir  of  Henry  C.  Carey. 

By  DR.  WM.  ELDER,    With  a  portrait.     8vo.,  cloth         .         .        75 

CAREY.— The  Works  of  Henry  C.  Carey  : 

Harmony  of  Interests  :    Agricultural,  Manufacturing  and  Commer. 

cial.     8vo.  .         .         $1.25 

Manual  of  Social  Science.  Condensed  from  Carey's  "  Principles 
of  Social  Science."  By  KATE  McKEAN.  I  vol.  12010.  .  $2.00 
Miscellaneous  Works.  With  a  Portrait.  2  vols.  8vo.  $10.00 

Past,  Present  and  Future.    8vo $2.50 

Principles  of  Social  Science.  3  volumes,  8vo.  .  .  $7.50 
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The  Unity  of  Law :  As  Exhibited  in  the  Relations  of  Physical, 
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CLARK. — Tramways,  their  Construction  and  Working  : 

Embracing  a  Comprehensive  History  of  the  System.  With  an  ex' 
haustive  analysis  of  the  various  modes  of  traction,  including  horse- 
power, steam,  heated  water  and  compressed  air ;  a  description  of  the 
varieties  of  Rolling  stock,  and  ample  details  of  cost  and  working  ex- 
penses.  By  D.  KINNEAR  CLARK.  Illustrated  by  over  200  wood 
engravings,  and  thirteen  folding  plates.  2  vols.  8vo.  .  $12.50 

COLBURN. — The  Locomotive  Engine  : 

Including  a  Description  of  its  Structure,  Rules  for  Estimating  its 
Capabilities,  and  Practical  Observations  on  its  Construction  and  Man- 
agement. By  ZERAH  COLBURN.  Illustrated.  I2mo.  .  $1.00 

COLLENS. — The  Eden  of  Labor ;  or,  the  Christian  Utopia. 
By  T.  WHARTON  COLLENS,  author  of  "  Humanics,"   "  The  History 
of  Charity,"  etc.     I2mo.     Paper  cover,  #1.00;  Cloth          .         #1.25 

COOLEY. — A  Complete  Practical  Treatise  on  Perfumery : 
Being  a  Hand-book  of  Perfumes,  Cosmetics  and  other  Toilet  Articles, 
With  a  Comprehensive    Collection  of  Formulae.     By  ARNOLD  J 
COOLEY.    i2mo $1.50 

COOPER.— A  Treatise  on  the  use  of  Belting  for  the  Trans- 
mission of  Power. 

With  numerous  illustrations  of  approved  and  actual  methods  of  ar- 
ranging Main  Driving  and  Quarter  Twist  Belts,  and  of  Belt  Fasten 
ings.  Examples  and  Rules  in  great  number  for  exhibiting  and  cal- 
culating the  size  and  driving  power  of  Belts.  Plain,  Particular  and 
Practical  Directions  for  the  Treatment,  Care  and  Management  o' 
Belts.  Descriptions  of  many  varieties  of  Beltings,  together  witn 
chapters  on  the  Transmission  of  Power  by  Ropes ;  by  Iron  and 
Wood  Frictional  Gearing ;  on  the  Strength  of  Belting  Leather ;  and 
on  the  Experimental  Investigations  of  Morin,  Briggs,  and  others.  By 
JOHN  H.  COOPER,  M.  E.  8vo $3.50 

CRAIK. — The  Practical  American  Millwright  and  MUler. 
By  DAVID  CRAIK,  Millwright.     Illustrated  by  numerous  wood  eiv- 
gravings  and  two  folding  plates.     $YQt        ...»         $3. 50 


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CREW.  —  A  Practical  Treatise  on  Petroleum  : 

Comprising  its  Origin,  Geology,  Geographical  Distribution,  History, 
Chemistry,  Mining,  Technology,  Uses  and  Transportation.  Together 
with  a  Description  of  Gas  Wells,  the  Application  of  Gas  as  Fuel,  etc. 
By  BENJAMIN  J.  CREW.  With  an  Appendix  on  the  Product  and 
Exhaustion  of  the  Oil  Regions,  and  the  Geology  of  Natural  Gas  in 
Pennsylvania  and  New  York.  By  CHARLES  A.  ASHBURNER,  M.  S., 
Geologist  in  Charge  Pennsylvania  Survey,  Philadelphia.  Illustrated 
by  70  engravings.  8vo.  508  pages  ....  $$.OO 

CROSS.  —  The  Cotton  Yarn  Spinner  : 

Showing  how  the  Preparation  should  be  arranged  for  Different 
Counts  of  Yarns  by  a  System  more  uniform  than  has  hitherto  been 
practiced;  by  having  a  Standard  Schedule  from  which  we  make  all 
our  Changes.  By  RICHARD  CROSS.  122  pp.  I2mo.  .  75 

CRISTIANI.—  A  Technical  Treatise  on  Soap  and  Candles: 
With  a  Glance  at  the  Industry  of  Fats  and  Oils.     By  R.  S.  CRIS- 
TIANI, Chemist.     Author  of  "Perfumery  and  Kindred  Arts."     Illus- 
trated by  176  engravings.     581  pages,  8vo.         .         .         .       $15.00 

CRISTIANI.—  Perfumery  and  Kindred  Arts: 

A  Comprehensive  Treatise  on  Perfumery,  containing  a  History  of 
Perfumes  from  the  remotest  ages  to  the  present  time.  A  complete 
detailed  description  of  the  various  Materials  and  Apparatus  used  in 
the  Perfumer's  Art,  with  thorough  Practical  Instruction  and  careful 
Formulae,  and  advice  for  the  fabrication  of  all  known  preparations  of 
the  day,  including  Essences,  Tinctures,  Extracts,  Spirits,  Waters, 
Vinegars,  Pomades,  Powders,  Paints,  Oils,  Emulsions,  Cosmetics, 
Infusions,  Pastilles,  Tooth  Powders  and  Washes,  Cachous,  Hair  Dyes, 
Sachets,  Essential  Oils,  Flavoring  Extracts,  etc.  ;  and  full  details  for 
making  and  manipulating  Fancy  Toilet  Soaps,  Shaving  Creams,  etc, 
by  new  and  improved  methods.  With  an  Appendix  giving  hints  and 
advice  for  making  and  fermenting  Domestic  Wines,  Cordials,  Liquors, 
Candies,  Jellies,  Syrups,  Colors,  etc.,  and  for  Perfuming  and  Flavor- 
ing Segars,  Snuff  and  Tobacco,  and  Miscellaneous  Receipts  foi 
various  useful  Analogous  Articles.  By  R.  S.  CRISTIANI,  Con- 
sulting Chemist  and  Perfumer,  Philadelphia.  8vo.  .  .  $10.00 

DAVIDSON.  —  A  Practical  Manual  of  House  Painting,  Grain- 

ing, Marbling,  and  Sign-Writing: 

Containing  full  information  on  the  processes  of  House  Painting  in 
Oil  and  Distemper,  the  Formation  of  Letters  and  Practice  of  Sign- 
Writing,  the  Principles  of  Decorative  Art,  a  Course  of  Elementary 
Drawing  for  House  Painters,  Writers,  etc.,  and  a  Collection  of  Useful 
Receipts.  With  nine  colored  illustrations  of  Woods  and  Marbles, 
and  numerous  wood  engravings.  By  ELLIS  A.  DAVIDSON.  I2mo. 


DA  VIES.  —A   Treatise  on    Earthy  and   Other   Minerals   and 

Mining  : 

By  D.  C  DA  VIES,  F.  G.  S.,  Mining  Engineer,  etc.     Illustrated  by 
76  Engravings.     I2mo.     .......         $5-°° 


io          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

DA  VIES.— A  Treatise  on  Metalliferous  Minerals  and  Mining: 
By  D.  C.  DAVIES,  F.  G.  S.7  Mining  Engineer,  Examiner  of  Mines. 
Quarries  and  Collieries.    Illustrated  by  148  engravings  of  Geological 
Formations,    Mining   Operations   and   Machinery,   drawn   from   th« 
practice  of  all  parts  of  the  world.    2d  Edition,  I2mo.,  450  pages  $5.00 

DAVIES. — A  Treatise  on  Slate  and  Slate  Quarrying: 

Scientific,  Practical  and  Commercial.  By  D.  C.  DAVIES,  F.  G.  S., 
Mining  Engineer,  etc.  With  numerous  illustrations  and  folding 
plates.  lamo $2.00 

DAVIS. — A  Treatise  on  Steam-Boiler  Incrustation  and  Meth- 
ods for  Preventing  Corrosion  and  the  Formation  of  Scale  : 
By  CHARLES  T.  DAVIS.     Illustrated  by  65  engravings.     8vo.    $1.50 
DAVIS. — The  Manufacture  of  Paper: 

Being  a  Description  of  the  various  Processes  for  the  Fabrication, 
Coloring  and  Finishing  of  every  kind  of  Paper,  Including  the  Dif- 
ferent Raw  Materials  and  the  Methods  for  Determining  their  Values, 
the  Tools,  Machines  and  Practical  Details  connected  with  an  intelli- 
gent and  a  profitable  prosecution  of  the  art,  with  special  reference  to 
the  best  American  Practice.  To  which  are  added  a  History  of  Pa- 
per, complete  Lists  of  Paper-Making  Materials,  List  of  American 
Machines,  Tools  and  Processes  used  in  treating  the  Raw  Materials, 
and  in  Making,  Coloring  and  Finishing  Paper.  By  CHARLES  T. 
DAVIS.  Illustrated  by  156  engravings.  608  pages,  8vo.  |6.oo 

DAVIS. — The  Manufacture  of  Leather: 

Being  a  description  of  all  of  tt     Processes  for  the  Tanning,  Tawing, 
Currying,  Finishing  and  Dyeing  of  every  kind  of  Leather  ;  including 
the  various  Raw  Materials  and   the  Methods  for  Determining  their 
Values;  the  Tools,   Machines,  and  all  Details  of  Importance  con- 
nected with  an  Intelligent  ami  Profitable  Prosecution  of  the  Art,  with 
Special  Reference  to  the  Best  American   Practice.     To  which  are 
added  Complete  Lists  of  all  American  Patents  for  Materials,  Pro- 
cesses, Tools,  and  Machines  for  Tanning,  Currying,  etc.   By  CHARLES 
THOMAS  DAVIS.     Illustrated  by  302  engravings  and  12  Samples  of 
Dyed  Leathers.     One  vol.,  8vo.,  824  pages        .        .         .      $10.00 
DAWIDOWSKY— BRANNT.— A   Practical  Treatise  on  the 
Raw  Materials  and  Fabrication  of  Glue,  Gelatine,  Gelatine 
Veneers  and  Foils,  Isinglass,  Cements,  Pastes,  Mucilages, 
etc.: 

Based  upon  Actual  Experience.  By  F.  DAWIDOWSKY,  Technical 
Chemist.  Translated  from  the  German,  with  extensive  additions, 
including  a  description  of  the  most  Recent  American  Processes,  by 
WILLIAM  T.  BRANNT,  Graduate  of  the  Royal  Agricultural  College 
of  Eldena,  Prussia.  35  Engravings.  I2mo.  .  .  .  #2.50 
DE  GRAFF. — The  Geometrical  Stair-Builders'  Guide : 

being  a  Plain  Practical  System  of  Hand-Railing,  embracing  all  itf 
necessary  Details,  and  Geometrically  Illustrated  by  twenty-two  Steel 
Engravings ;  together  with  the  use  of  the  most  approved  principles 
of  Practical  Geometry.  By  SIMON  DE  GRAFF,  Architect.  *te. 

#2.50 


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DE  KONINCK— DIETZ.— A  Practical  Manual  of  Chemical 

Analysis  and  Assaying : 

As  applied  to  the  Manufacture  of  Iron  from  its  Ores,  and  to  Cast  Iron, 
Wrought  Iron,  and  Steel,  as  found  in  Commerce.  By  L.  L.  DH 
KONINCK,  Dr.  Sc.,  and  E.  DIETZ,  Engineer.  Edited  with  Notes,  by 
ROBERT  MALLET,  F.  R.  S.,  F.  S.  G.,  M.  I.  C.  E.,  etc.  American 
Edition,  Edited  with  Notes  and  an  Appendix  on  Iron  Ores,  by  A.  A. 
FESQUET,  Chemist  and  Engineer.  I2mo.  --.  .  .  $1.50 

DUNCAN.— Practical  Surveyor's  Guide: 

Containing  the  necessary  information  to  make  any  person  of  COIM 
mon  capacity,  a  finished  land  surveyor  without  the  aid  of  a  teacher 
By  ANDREW  DUNCAN.  Revised.  72  engravings,  2 14  pp.  I2mo.  $1.50 

DUPLAIS.— A  Treatise  on  the  Manufacture  and  Distillation 

of  Alcoholic  Liquors : 

Comprising  Accurate  and  Complete  Details  in  Regard  to  Alcohol 
from  Wine,  Molasses,  Beets,  Grain,  Rice,  Potatoes,  "Sorghum,  Aspho 
del,  Fruits,  etc. ;  with  the  Distillation  and  Rectification  of  Brandy. 
Whiskey,  Rum,  Gin,  Swiss  Absinthe,  etc.,  the  Preparation  of  Aro- 
matic Waters,  Volatile  Oils  or  Essences,  Sugars,  Syrups,  Aromatic 
Tinctures,  Liqueurs,  Cordial  Wines,  Effervescing  Wines,  etc.,  the 
Ageing  of  Brandy  and  the  improvement  of  Spirits,  with  Copiom 
Directions  and  Tables  for  Testing  and  Reducing  Spirituous  Liquors, 
etc.,  etc.  Translated  and  Edited  from  the  French  of  MM.  DUPLAIS, 
Aine  et  Jeune.  By  M.  McKENNiE,  M.  D.  To  which  are  added  the 
United  States  Internal  Revenue  Regulations  for  the  Assessment  and 
Collection  of  Taxes  on  Distilled  Spirits.  Illustrated  by  fourteen 
folding  plates  and  several  wood  engravings.  743  pp.  8vo.  $10  oo 

DUSSAUCE.— Practical  Treatise  on  the  Fabrication  of  Matches, 

Gun  Cotton,  and  Fulminating  Powder. 
By  Professor  H.  DUSSAUCE.     I2mo.          .         .         .         .        $3  oo 

DYER  AND  COLOR-MAKER'S  COMPANION: 

Containing  upwards  of  two  hundred  Receipts  for  making  Colors,  on 
the  most  approved  principles,  for  all  the  various  styles  and  fabrics  novr 
in  existence;  with  the  Scouring  Process,  and  plain  Directions  for 
Preparing,  Washing-off,  and  Finishing  the  Goods.  I2mo.  $1.00 

EDWARDS. — A  Catechism  of  the  Marine  Steam-Engine, 
For  the  use  of  Engineers,  Firemen,  and  Mechanics.  A  Practical 
Work  for  Practical  Men.  By  EMORY  EDWARDS,  Mechanical  Engi- 
neer. Illustrated  by  sixty-three  Engravings,  including  examples  of 
the  most  modern  Engines.  Third  edition,  thoroughly  revised,  with 
much  additional  matter.  I2mo.  414  pages  $2  oo 

EDWARDS. — Modern  American  Locomotive  Engines, 
Their  Design,  Construction  and  Management.     By  EMORY  EDWARDS* 
Illustrated  I2mo $2.00 

EDWARDS. — The  American  Steam  Engineer: 

Theoretical  and  Practical,  with  examples  of  the  latest  and  most  ap- 
proved American  practice  in  the  design  and  construction  of  Steam 
Engines  and  Boilers.  For  the  use  of  engineers,  machinists,  boiler- 
leakers,  and  engineering  students.  By  EMORY  EDWARDS.  Fully 
illustrated,  419  pages.  121110.  «...  $2. go 


12         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

EDWARDS. — Modern  American  Marine  Engines,  Boilers,  ant 
Screw  Propellers, 

Their  Design  and  Construction.  Showing  the  Present  Practice  ot 
the  most  Eminent  Engineers  and  Marine  Engine  Builders  in  the 
United  States.  Illustrated,  by  30  large  and  elaborate  plates.  410.  $5.00 
EDWARDS. — The  Practical  Steam  Engineer's  Guide 
In  the  Design,  Construction,  and  Management  of  American  Stationary, 
Portable,  and  Steam  Fire- Engines,  Steam  Pumps,  Boilers,  Injectors, 
Governors,  Indicators,  Pistons  and  Rings,  Safety  Valves  and  Steam 
Gauges.  For  the  use  of  Engineers,  Firemen,  and  Steam  Users.  By 
EMORY  EDWARDS.  Illustrated  by  119  engravings.  420  pages. 
121110 $2  50 

EISSLER.— The  Metallurgy  of  Gold  : 

A  Practical  Treatise  on  the  Metallurgical  Treatment  of  Gold-Bear- 
ing  Ores,  including  the  Processes  of  Concentration  and  Chlorination, 
and  the  Assaying,  Melting,  and  Refining  of  Gold.  By  M.  EISSLER. 
With  132  Illustrations.  I2mo. $3.50 

EISSLER.— The  Metallurgy  of  Silver  : 

A  Practical  Treatise  on  the  Amalgamation,  Roasting,  and  Lixiviation 
of  Silver  Ores,  including  the  Assaying,  Meliing,  and  Refining  of 
Silver  Bullion.  By  M.  EISSLER.  124  Illustrations.  336  pp. 
I2mo $4.25 

ELDER. — Conversations  on  the  Principal  Subjects  of  Political 

Economy. 
By  DR.  WILLIAM  ELDER.    8vo #2.50 

ELDER. — Questions  of  the  Day, 

Economic  and  Social.     By  DR.  WILLIAM  ELDER.    8vo.     .      $3.00 

ERNI.— Mineralogy  Simplified. 

Easy  Methods  of  Determining  and  Classifying  Minerals,  including 
Ores,  by  means  of  the  Blowpipe,  and  by  Humid  Chemical  Analysis, 
based  on  Professor  von  Kobell's  Tables  for  the  Determination  of 
Minerals,  with  an  Introduction  to  Modern  Chemistry.  By  HENRY 
ERNI,  A.M.,  M.D.,  Professor  of  Chemistry.  Second  Edition,  rewritten, 
enlarged  and  improved.  I2mo.  .  .  .  .  •  $>3OC 

FAIRBAIRN.— The  Principles  of  Mechanism  and  Machinery 

of  Transmission  • 

Comprising  the  Principles  of  Mechanism,  Wheels,  and  Pullevs, 
Strength  and  Proportions  of  Shafts,  Coupling  of  Shafts,  and  Engag- 
ing  and  Disengaging  Gear.  By  SIR  WILLIAM  FAIRBAIRN,  Bait 
C.  E.  Beautifully  Illustrated  by  over  150  wood-cuts.  In  one 
volume.  I2mo #2.50 

FLEMING. — Narrow  Gauge  Railways  in  America. 

A  Sketch  of  their  Rise,  Progress,  and  Success.  Valuable  Statistics 
as  to  Grades,  Curves,  Weight  of  Rail,  Locomotives,  Cars,  etc.  By 
HOWARD  FLEMING.  Illustrated,  8vo $1  oo 

FORSYTH.— Book  of   Designs  for  Headstones,   Mural,   and 

other  Monuments: 

Containing  78  Designs.  By  JAMES  FORSYTH.  With  an  Introduction 
Vy  CHARLES  BOUTELL,  M.  A.  4  to.,  cloth  .  .  -  $5  w 


HENRY   CAREY   BAIRD   &  CO.'S   CATALOGUE. 


FRANKEL— HUTTER.— A  Practical  Treatise  on  the  Manu- 
facture of  Starch,  Glucose,  Starch-Sugar,  and  Dextrine: 
Based  on  the  German  of  LADISLAUS  VON  WAGNER,  Professor  in  the 
Royal  Technical  High  School,  Buda-Pest,  Hungary,  and  other 
authorities.  By  JULIUS  FRANKEL,  .Graduate  of  the  Polytechnic 
School  of  Hanover.  Edited  by  ROBERT  HUTTER,  Chemist,  Practical 
Manufacturer  of  Starch-Sugar.  Illustrated  by  58  engravings,  cover- 
ing every  branch  of  the  subject,  including  examples  of  the  most 
Recent  and  Best  American  Machinery.  8vo.,  344  pp.  .  $3 .50 

GARDNER. — The  Painter's  Encyclopaedia: 

Containing  Definitions  of  all  Important  Words  in  the  Art  of  Plain 
and  Artistic  Painting,  with  Details  of  Practice  in  Coach,  Carriage, 
Railway  Car,  House,  Sign,  and  Ornamental  Painting,  including 
Graining,  Marbling,  Staining,  Varnishing,  Polishing,  Lettering, 
Stenciling,  Gilding,  Bronzing,  etc.  By  FRANKLIN  B.  GARDNER. 
158  Illustrations.  I2ino.  427  pp $2.00 

GARDNER. — Everybody's  Paint  Book: 

A  Complete  Guide  to  the  Art  of  Outdoor  and  Indoor  Painting,  De- 
signed for  the  Special  Use  of  those  who  wish  to  do  their  own  work, 
and  consisting  of  Practical  Lessons  in  Plain  Painting,  Varnishing, 
Polishing,  Staining,  P?prr  Hanging,  Kalsomining,  etc.,  as  well  as 
Directions  for  Renovating  Furniture,  and  Hints  on  Artistic  Work  for 
Home  Decoration.  38  Illustrations.  I2mo.,  183  pp.  .  $1.00 

GEE.— The  Goldsmith's  Handbook : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Gold, 
including  the  Art  of  Alloying,  Melting,  Reducing,  Coloring,  Col- 
lecting,  and  Refining;  the  Processes  of  Manipulation,  Recovery  of 
Waste;  Chemical  and  Physical  Properties  of  Gold;  with  a  New 
System  of  Mixing  its  Alloys ;  Solders,  Enamels,  and  other  Useful 
Rules  and  Recipes.  By  GEORGE  E.  GEE.  I2mo.  .  .  $1*7$ 

GEE. — The  Silversmith's  Handbook  : 

Containing  full  instructions  for  the  Alloying  and  Working  of  Silver, 
including  the  different  modes  of  Refining  and  Melting  the  Metal ;  its 
Solders ;  the  Preparation  of  Imitation  Alloys ;  Methods  of  Manipula- 
tion ;  Prevention  of  Waste  ;  Instructions  for  Improving  and  Finishing 
the  Surface  of  the  Work ;  together  with  other  Useful  Information  and 

•  Memoranda.     By  GEORGE  E.  GEE.     Illustrated.     I2mo.        $1-75 

GOTHIC  ALBUM  FOR  CABINET-MAKERS: 

Designs  for  Gothic  Furniture.     Twenty-three  plates.     Oblong  $2.OO 

GRANT. — A  Handbook  on  the  Teeth  of  Gears  : 
Their  Curves,  Properties,  and  Practical  Construction.     By  GEORGE 
B.  GRANT.     Illustrated.     Third  Edition,  enlarged.     8vo.          $1.00 

GREENWOOD.— Steel  and  Iron: 

Comprising  the  Practice  and  Theory  of  the  Several  Methods  Pur- 
sued in  their  Manufacture,  and  of  their  Treatment  in  the  Rolling- 
Mills,  the  Forge,  and  the  Foundry.  By  WILLIAM  HENRY  GREEN- 
WOOD, F.  C.  S.  With  97  Diagrams,  536  pages.  12010.  $2.00 


14       HENRY   CAREY   BAIRD   &   CO.'S  CATALOGUE. 


GREGORY.— Mathematics  for  Practical  Men : 

Adapted  to  the  Pursuits  of  Surveyors,  Architects,  Mechanics,  and 
Civil  Engineers.  By  OLINTHUS  GREGORY.  8vo.,  plates  $3.00 

GRISWOLD.— Railroad  Engineer's  Pocket  Companion  for  UK 

Field: 

Comprising  Rules  for  Calculating  Deflection  Distances  and  Angles, 
Tangential  Distances  and  Angles,  and  all  Necessary  Tables  for  En 
gineers;  also  the  Art  of  Levelling  from  Preliminary  Survey  to  the 
Construction  of  Railroads,  intended  Expressly  for  the  Young  En- 
gineer, together  with  Numerous  Valuable  Rules  and  Examples.  By 
W.  GRISWOLD.  i2mo.,  tucks *  $*-75 

GRUNER.— Studies  of  Blast  Furnace  Phenomena: 

By  M.  L.  GRUNER,  President  of  the  General  Council  of  Mines  o! 
France,  and  lately  Professor  of  Metallurgy  at  the  Ecole  des  Mines. 
Translated,  with  the  author's  sanction,  with  an  Appendix,  by  L.  D. 
B.  GORDON,  F.  R.  S.  E.,  F.  G.  S.  8vo.  .  .  .  $2.50 

Hand-Book  of  Useful  Tables  for  the  Lumberman,  Farmer  and 

Mechanic : 

Containing  Accurate  Tables  of  Logs  Reduced  to  Inch  Board  Meas* 
ure,  Plank,  Scantling  and  Timber  Measure;  Wages  and  Rent,  by 
Week  or  Month ;  Capacity  of  Granaries,  Bins  and  Cisterns ;  Land 
Measure,  Interest  Tables,  with  Directions  for  Finding  the  Interest  on 
any  sum  at  4,  5,  6,  7  and  8  per  cent.,  and  many  other  Useful  Tables. 
32  mo.,  boards.  186  pages .25 

HASERICK.— The  Secrets  of  the  Art  of  Dyeing  Wool,  Cotton, 

and  Linen, 

Including  Bleaching  and  Coloring  Wool  and  Cotton  Hosiery  and 
Random  Yarns.  A  Treatise  based  on  Economy  and  Practice.  By 
E.  C.  HASERICK.  Illustrated  by  323  Dyed  Patterns  of  the  Yarn* 
or  Fabrics.  8vo $7-5o 

HATS  AND  FELTING: 

A  Practical  Treatise  on  their  Manufacture.  By  a  Practical  Hatter. 
Illustrated  by  Drawings  of  Machinery,  etc.  8vo.  .  .  #1.25 

HOFFER. — A   Practical   Treatise  on   Caoutchouc  and  Gutta 

Percha, 

Comprising  the  Properties  of  the  Raw  Materials,  and  the  manner  or" 
Mixing  and  Working  them ;  with  the  Fabrication  of  Vulcanized  and 
Hard  Rubbers,  Caoutchouc  and  Gutta  Pescha  Compositions,  Water* 
proof  Substances,  Elastic  Tissues,  the  Utilization  of  Waste,  etc.,  etc, 
From  the  German  of  RAIMUND  H©FFER.  By  W.  T.  BRANNT. 
Illustrated  I2mo $2.50 

HAUPT.— Street  Railway  Motors: 

With  Descriptions  and  Cost  of  Plants  and  Operation  of  the  Various 
Systems  now  in  Use.  I2mo.  ,  ....  $1-75 


HENRY   CAREY   BAIRD   &   CO.'S   CATALOGUE.        15 

HAUPT— RHAWN.— A  Move  for  Better  Roads  : 

Essays  on  Road-making  and  Maintenance  and  Road  Laws,  for 
which  Prizes  or  Honorable  Mention  were  Awarded  through  the 
University  of  Pennsylvania  by  a  Committee  of  Citizens  of  Philadel- 
phia, with  a  Synopsis  of  other  Contributions  and  a  Review  by  the 
Secretary,  LEWIS  M.  HAUPT,  A.  M.,  C.  E. ;  also  an  Introduction  by 
WILLIAM  H.  RHAWN,  Chairman  of  the  Committee.  319  pages. 
8vo. $2.00 

HUGHES. — American  Miller  and  Millwright's  Assistant: 
By  WILLIAM  CARTER  HUGHES.    i2mo $1.50 

HULME. — Worked  Examination  Questions  in  Plane  Geomet- 
rical Drawing : 

For  the  Use  of  Candidates  for  the  Royal  Military  Academy,  Wool- 
wich ;  the  Royal  Military  College,  Sandhurst ;  the  Indian  Civil  En- 
gineering College,  Cooper's  Hill ;  Indian  Public  Works  and  Tele- 
graph  Departments ;  Royal  Marine  Light  Infantry ;  the  Oxford  and 
Cambridge  Local  Examinations,  etc.  By  F.  EDWARD  HULME,  F.  L. 
S.,  F.  S.  A.,  Art-Master  Marlborough  College.  Illustrated  by  300 
examples.  Small  quarto $2.50 

JERVIS. — Railroad  Property: 

A  Treatise  on  the  Construction  and  Management  of  Railways; 
designed  to  afford  useful  knowledge,  in  the  popular  style,  to  the 
holders  of  this  class  of  property ;  as  well  as  Railway  Manage*,  Offi- 
cers, ar.d  Agents.  By  JOHN  B.  JERVIS,  late  Civil  Engineer  of  the 
Hudson  River  Railroad,  Croton  Aqueduct,  etc.  i2mo.,  cloth  $2.oc 

KEENE.— A  Hand-Book  of  Practical  Gauging: 

For  the  Use  of  Beginners,  to  which  is  added  a  Chapter  on  Distilla- 
tion, describing  the  process  in  operation  at  the  Custom-House  for 
ascertaining  the  Strength  of  Wines.  By  JAMES  B.  KEENE,  of  H.  M. 
Customs.  8vo. $1^25 

KELLEY. — Speeches,  Addresses,  and  Letters  on  Industrial  and 

Financial  Questions : 
By  HON.  WILLIAM  D.  KELLEY,  M.  C.     544  pages,  8vo.  .        $2.50 

KELLOGG. — A  New  Monetary  System  : 

The  only  means  of  Securing  the  respective  Rights  of  Labor  and 
Property,  and  of  Protecting  the  Public  from  Financial  Revulsions, 
By  EDWARD  KELLOGG.  Revised  from  his  work  on  "Labor  and 
other  Capital."  With  numerous  additions  from  his  mnnuscript. 
Edited  by  MARY  KELLOGG  PUTNAM.  Fifth  edition.  To  which  in 
added  a  Biographical  Sketch  of  the  Author.  One  rolume,  izmo. 

Paper  cover $l.oo 

Bound  in  cloth 1.50 

KEMLO.— Watch-Repairer's  Hand-Book : 
Being  a  Complete  Guide  to  the  Young  Beginner,  in  Taking  Apart, 
Putting  Together,  and  Thoroughly  Cleaning  the  English  Lever  and 
other  Foreign  Watches,  and  all  American  Watches.     By  F.  KEMLO, 
Practical  Watchmaker.     With  Illustrations.     I2tno.  .        $1.25 


16          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

XENTISH.— A  Treatise  on  a  Box  of  Instruments, 

And  the  Slide  Rule ;  with  the  Theory  of  Trigonometry  and  Log* 
rithms,  including  Practical  Geometry,  Surveying,  Measuring  of  Tim- 
ber,  Cask  and  Malt  Gauging,  Heights,  and  Distances.  By  THOMAJ 
KENTISH.  In  one  volume.  I2mo.  ....  $1.2 

KERL.— The  Assayer's  Manual: 

An  Abridged  Treatise  on  the  Docimastic  Examination  of  Ores,  and 
Furnace  and  other  Artificial  Products.  By  BRUNO  KERL,  Professor 
in  the  Royal  School  of  Mines.  Translated  from  the  German  by 
WILLIAM  T.  BRANNT.  Second  American  edition,  edited  with  Ex- 
tensive Additions  by  F.  LYNWOOD  GARRISON,  Member  of  the 
American  Institute  of  Mining  Engineers,  etc.  Illustrated  by  87  en- 
gravings. 8vo #3-OO 

KICK. — Flour  Manufacture . 

A  Treatise  on  Milling  Science  and  Practice.  By  FREDERICK  KICK, 
Imperial  Regierungsrath,  Professor  of  Mechanical  Technology  in  the 
Imperial  German  Polytechnic  Institute,  Prague.  Translated  from 
the  second  enlarged  and  revised  edition  with  supplement  by  H.  H. 
P.  POWLES,  Assoc.  Memb.  Institution  of  Civil  Engineers.  Illustrated 
with  28  Platens,  and  167  Wood-cuts.  367  pages.  8vo.  .  $10.00 

KINGZETT. — The   History,  Products,  and   Processes  of  the 

Alkali  Trade : 

Including  the  most  Recent  Improvements.  By  CHARLES  THOMAS 
KINGZETT,  Consulting  Chemist.  With  23  illustrations.  8vo.  $2.50 

KIRK.— The  Founding  of  Metals : 

A  Practical  Treatise  on  the  Melting  of  Iron,  with  a  Description  of  the 
Founding  of  Alloys ;  also,  of  all  the  Metals  and  Mineral  Substancei 
used  in  the  Art  of  Founding.  Collected  from  original  sources.  B> 
EDWARD  KIRK,  Practical  Foundryman  and  Chemist.  Illustrated. 
Third  edition.  8vo. $2.50 

LANDRIN.— A  Treatise  on  Steel : 

Comprising  its  Theory,  Metallurgy,  Properties,  Practical  Working, 
and  Use.  By  M.  H.  C.  LANDRIN,  JR.,  Civil  Engineer.  Translated 
from  the  French,  with  Notes,  by  A.  A.  FESQUET,  Chemist  and  En 
gineer.  With  an  Appendix  on  the  Bessemer  and  the  Martin  Pro- 
cesses for  Manufacturing  Steel,  from  the  Report  of  Abram  S.  Hawitt, 
United  States  Commissioner  to  the  Universal  Exposition,  Paris,  1867] 
I2mo fo-00 

LANGBEIN. — A  Complete  Treatise  on  the  Electro-Deposition 

of  Metals : 

Translated  from  the  German,  with  Additions,  by  WM.  T.  BRANNT. 
125  illustrations.  8vo $4.00 

LARD NER.— The  Steam-Engine : 

For  the  Use  of  Beginners.     Illustrated.     I2rno.    ...         75 

LEHNER.— The  Manufacture  of  Ink: 

Comprising  the  Raw  Materials,  and  the  Preparation  of  Writing, 
Copying  and  Hektograph  Inks,  Safety  Inks,  Ink  Extracts  and  Pow- 
ders, etc.  Translated  from  the  German  of  SlGMUND  LEHNER,  with 
additions  by  WILLIAM  T.  BRANNT.  Illustrated.  I2mo.  $2.00 


HENRY  CAREY    BAIRD   &  CO.'S  CATALOGUE.        17 

LARKIN. — The  Practical  Brass  and  Iron  Founder's  Guide: 
A  Concise  Treatise  on  Brass  Founding,  Moulding,  the  Metals  and 
their  Alloys,  etc. ;  to  which  are  added  Recent  Improvements  in  the 
Manufacture  of  Iron,  Steel  by  the  Bessemer  Process,  etc.,  etc.  Bf 
JAMES  LARKIN,  late  Conductor  of  the  Brass  Foundry  Department  U 
Reany,  Neafie  &  Co.'s  Penn  Works,  Philadelphia.  New  edition, 
revised,  with  extensive  additions.  I2mo.  .  .  .  #2.50 

LEROUX. — A    Practical     Treatise    on    the    Manufacture    of 

Worsteds  and  Carded  Yarns : 

Comprising  Practical  Mechanics,  with  Rules  and  Calculations  applied 
to  Spinning;  Sorting,  Cleaning,  and  Scouring  Wools;  the  English 
and  French  Methods  of  Combing,  Drawing,  and  Spinning  Worsteds, 
and  Manufacturing  Carded  Yarns.  Translated  from  the  French  of 
CHARLES  LEROUX,  Mechanical  Engineer  and  Superintendent  of  a 
Spinning-Mill,  by  HORATIO  PAINE,  M.  D.,  and  A.  A.  FESQUET, 
Chemist  and  Engineer.  Illustrated  by  twelve  large  Plates.  To  which 
is  added  an  Appendix,  containing  Extracts  from  the  Reports  of  the 
International  Jury,  and  of  the  Artisans  selected  by  the  Commtttes 
appointed  by  the  Council  of  the  Society  of  Arts,  London,  on  Woolen 
and  Worsted  Machinery  and  Fabrics,  as  exhibited  in  the  Paris  Uni- 
versal Exposition,  1867.  8vo.  $5.00 

LEFFEL. — The  Construction  of  Mill-Dams : 
Comprising  also  the  Building  of  Race  and  Reservoir  Embankments 
and  Head-Gates,  the   Measurement  of  Streams,  Gauging  of  Water 
Supply,  etc.     By  JAMES  LEFFEL  &  Co.    Illustrated  by  58  engravings. 
8vo. $2.50 

LESLIE.— Complete  Cookery: 

Directions  for  Cookery  in  its  Various  Branches.  By  Miss  LESLIE. 
Sixtieth  thomsand.  Thoroughly  revised,  with  the  addition  of  New 
Receipts.  I2mo £1.50 

LE  VAN. — The  Steam  Engine  and  the  Indicator : 

Their  Origin  and  Progressive  Development;  including  the  Most 
Recent  Examples  of  Steam  and  Gas  Motors,  together  with  the  Indi- 
cator, its  Principles,  its  Utility,  and  its  Application.  By  WILLIAM 
BARNET  LE  VAN.  Illustrated  by  205  Engravings,  chiefly  of  Indi- 
cator-Cards. 469  pp.  8vo $4-°o 

LIEBER. — Assayer's  Guide  : 

Or,  Practical  Directions  to  Assayers,  Miners,  and  Smelters,  for  the 
Tests  and  Assays,  by  Heat  and  by  Wet  Processes,  for  the  Ores  of  all 
the  principal  Metals,  of  Gold  and  Silver  Coins  and  Alloys,  and  of 
Coal,  etc.  By  OSCAR  M.  LIEBER.  Revised.  283  pp.  I2mo.  $1.50 

JLockwood's  Dictionary  of  Terms  : 

Used  in  the  Practice  of  Mechanical  Engineering,  embracing  those 
Current  in  the  Drawing  Office,  Pattern  Shop,  Foundry,  Fitting,  Turn- 
ing, Smith's  and  Boiler  Shops,  etc.,  etc.,  comprising  upwards  of  Six' 
Thousand  Definitions.  Edited  by  a  Foreman  Pattern  Maker,  author 
«f  "  Pattern  Making."  417  pp.  I2tno.  .  .  ^  Ifl.oo 


i8         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

LUKIN.— Amongst  Machines ; 

Embracing  Descriptions  of  the  various  Mechanical  Appliances  used 
in  the  Manufacture  of  Wood,  Metal,  and  other  Substances.  I2mo. 

JM-75 
LUKIN.— The  Boy  Engineers : 

What  They  Did,  and  How  They  Did  It.     With  30  plates.     l8mo. 

#1-75 

LUKIN.— The  Young  Mechanic  t 

Practical  Carpentry.  Containing  Directions  for  the  Use  of  all  kinds 
t>f  Tools,  and  for  Construction  of  Steam- Engines  and  Mechanical 
Models,  including  the  Art  of  Turning  in  Wood  and  Metal.  By  JOHN 
LUKIN,  Author  of  "The  Lathe  and  Its  Uses,"  etc.  Illustrated. 
I2mo $1-75 

MAIN  and  BROWN.— Questions  on  Subjects  Connected  with 

the  Marine  Steam-Engine : 

And  Examination  Papers;  with  Hints  for  their  Solution.  By 
THOMAS  J.  MAIN,  Professor  of  Mathematics,  Royal  ""tfaval  College, 
and  THOMAS  BROWN,  Chief  Engineer,  R.  N.  I2mo.,  cloth  .  #1.00 

MAIN  and  BROWN.— The  Indicator  and  Dynamometer: 
With  their  Practical  Applications  to  the  Steam-Engine.     By  THOMAS 
J.  MAIN,   M.  A.  F.  R.,  Ass't    S.   Professor   Royal   Naval   College, 
Portsmouth,  and  THOMAS  BROWN,  Assoc.  Inst.  C.  E.,  Chief  Engineer 
R.  N.,  attached  to  the  R.  N.  College.     Illustrated.     8vo.  .         #I.OO 

MAIN  and  BROWN.— The  Marine  Steam-Engine. 

By  THOMAS  J.  MAIN,  F.  R.  Ass't  S.  Mathematical  Professor  at  the 
Royal  Naval  College,  Portsmouth,  and  THOMAS  BROWN,  Assoc. 
Inst.  C.  E.,  Chief  Engineer  R.  N.  Attached  to  the  Royal  Naval 
College.  With  numerous  illustrations.  8vo. 

MAKINS.— A  Manual  of  Metallurgy: 

By  GEORGE  HOGARTH  MAKINS.  100  engravings.  Second  edition 
rewritten  and  much  enlarged.  I2mo.,  592  pages  .  .  $3-oo 

MARTIN.— Screw-Cutting  Tables,  for  the  Use  of  Mechanica) 

Engineers : 

Showing  the  Proper  Arrangement  of  Wheels  for  Cutting  the  Threads 
of  Screws  of  any  Required  Pitch ;  with  a  Table  for  Making  the  Uni- 
versal Gas-Pipe  Thread  and  Taps.  By  W.  A.  MARTIN,  Engineer. 
8vo. 50 

MICHELL.— Mine  Drainage: 

Being  a  Complete  and  Practical  Treatise  on  Direct-Acting  Under* 
ground  Steam  Pumping  Machinery.  With  a  Description  of  a  larg« 
nuuaber  of  the  best  known  Engines,  their  General  Utility  and  ih« 
Special  Sphere  of  their  Action,  the  Mode  of  their  Application,  and 
their  Merits  compared  with  other  Pumping  Machinery.  By  STEPHEN 
MICHELL.  Illustrated  by  137  engravings.  8vo.,  277  pages  .  $6.00 

MOLESWORTH.— Pocket-Book    of    Useful     Formulae     and 

Memoranda  for  Civil  and  Mechanical  Engineers. 
By  GUILFORD  L.  MOLESWORTH,  Member  of  the  Institution  of  Civil 
Engineers,  Chief  Resident   Engineer  of  the  Ceylon  Railway.     Full- 
bound  in  Pocket-book  form       .         .         .         ••         •         J>I.Ol 


HENRY  CAREY  BAIRD  &  CO.-ff  CATALOGUE.         19 

MOORE.— The  Universal  Assistant  and  the  Complete  Me- 
chanic : 

Containing  over  one  million  Industrial  Facts,  Calculations,  Receipts, 
Processes,  Trades  Secrets,  Rules,  Business  Forms,  Legal  Items,  Etc., 
in  every  occupation,  from  the  Household  to  the  Manufactory.  By 
R.  MOORE.  Illustrated  by  500  Engravings.  I2mo.  .  $2.50 

MORRIS. — Easy  Rules  for  the  Measurement  of  Earthworks : 
By  means  of  the  Prismoidal  Formula.  Illustrated  with  Numerom 
Wood- Cuts,  Problems,  and  Examples,  and  concluded  by  an  Exten- 
sive Table  for  finding  the  Solidity  in  cubic  yards  from  Mean  Areas. 
The  whole  being  adapted  for  convenient  use  by  Engineers,  Surveyors, 
Contractors,  and  others  needing  Correct  Measurements  of  Earthwork. 
By  ELWOOD  MORRIS,  C.  E.  8vo $1.50 

MAUCHLINE.— The  Mine  Foreman's  Hand-Book: 

Of  Practical  and  Theoretical  Information  on  the  Opening,  Ventilat- 
ing, and  Working  of  Collieries.  Questions  and  Answers  on  Practi- 
cal and  Theoretical  Coal  Mining.  Designed  to  Assist  Students  and 
others  in  Passing  Examinations  for  Mine  Foremanships.  A  New, 
Revised  and  Enlarged  Edition.  114  illustrations.  8vo.  $3-73 

NAPIER. — A  System  of  Chemistry  Applied  to  Dyeing. 

By  JAMES  NAPIER,  F.  C.  S.  A  New  and  Thoroughly  Revised  Edi- 
tion. Completely  brought  up  to  the  present  state  of  the  Science, 
including  the  Chemistry  of  Coal  Tar  Colors,  by  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  Appendix  on  Dyeing  and  Calica 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867.  Illus- 
trated. 8vo.  422  pages $3-5° 

NEVILLE.— Hydraulic  Tables,  Coefficients,  and  Formulae,  for 
finding  the  Discharge  of  Water  from  Orifices,  Notches, 
Weirs,  Pipes,  and  Rivers : 

Third  Edition,  with  Additions,  consisting  of  New  Formulas  for  the 
Discharge  from  Tidal  and  Flood  Sluices  and  Siphons ;  general  infor- 
mation on  Rainfall,  Catchment-Basins,  Drainage,  Sewerage,  Water 
Supply  for  Towns  and  Mill  Power.  By  TOHN  NEVILLE,  C.  E.  M  R 
I.  A. ;  Fellow  of  the  Royal  Geological  Society  of  Ireland.  Thick 
I2ino 15-50 

NEWBERY.—  Gleanings     from     Ornamental    Art    of    every 

style ; 

Drawn  from  Examples  in  the  British,  South  Kensington,  Indian, 
Crystal  Palace,  and  other  Museums,  the  Exhibitions  of  1851  and 
1862,  and  the  best  English  and  Foreign  works.  In  a  series  of  loo 
exquisitely  drawn  Plates,  containing  many  hundred  examples.  By 
ROBERT  NEWBERY.  410. $12.53 

NICHOLLS.  —The  Theoretical  and  Practical  Boiler-Maker  and 

Engineer's  Reference  Book: 

Containing  a  variety  of  Useful  Information  for  Employers  of  Labor. 
Foremen  and  Working  Boiler-Makers,  Iron,  Copper,  and  Tinsmith* 


20        HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

Ikaughismen,  Engineers,  the  General  Steam-using  Public,  and  for  tho 
Use  of  Science  Schools  and  Classes.  By  SAMUEL  NICHOLLS.  Illus- 
trated by  sixteen  plates,  I2mo.  .....  $2.50 

NICHOLSON.— A  Manual  of  the  Art  of  Bookbinding : 

Containing  full  instructions  in  the  different  Branches  of  Forwarding, 
Gilding,  and  Finishing.  Also,  the  Art  of  Marbling  Book-edges  and 
Paper.  By  JAMES  B.  NICHOLSON.  Illustrated.  I2mo.,  cloth  $2.2$ 

NICOLLS.— The  Railway  Builder: 

A  Hand-Book  for  Estimating  the  Probable  Cost  of  American  Rail* 
way  Construction  and  Equipment.  By  WILLIAM  J.  NICOLLS,  Civil 
Engineer.  Illustrated,  full  bound,  pocket-book  form  .  $2.00 

NORMANDY.— The  Commercial  Handbook  of  Chemical  An- 

alysis :  , 

Or  Practical  Instructions  for  the  Determination  of  the  Intrinsic  ot 
Commercial  Value  of  Substances  used  in  Manufactures,  in  Trades, 
and  in  the  Arts.  By  A.  NORMANDY.  New  Edition,  Enlarged,  and 
to  a  great  extent  rewritten.  By  HENRY  M.  NOAD,  Ph.D.,  F.R.S., 
thick  I2mo $5.00 

NORRIS. — A  Handbook  for  Locomotive   Engineers  and  Ma- 
chinists : 

Comprising  the  Proportions  and  Calculations  for  Constructing  Loco- 
motives; Manner  of  Setting  Valves;  Tables  of  Squares,  Cubes,  Areas, 
etc.,  etc.  By  SEPTIMUS  NORRIS,  M.  E.  New  edition.  Illustrated, 
I2mo |i.50 

NYSTROM.— A  New  Treatise  on  Elements  of  Mechanics : 
Establishing  Strict  Precision  in  the   Meaning  of  Dynamical  Terms : 
accompanied  with  an  Appendix  on  Duodenal  Arithmetic  and   Me- 
trology.    By  JOHN  W.  NYSTROM,  C.  E.     Illustrated.     8vo.       $2.00 

NYSTROM. — On  Technological  Education  and  the  Construc- 
tion of  Ships  and  Screw  Propellers : 

For  Naval  and  Marine  Engineers.  By  JOHN  W.  NYSTROM,  late 
Acting  Chief  Engineer,  U.  S.  N.  Second  edition,  revised,  with  addi- 
tional matter.  Illustrated  by  seven  engravings.  I2mo.  .  $1.50 

O'NEILL. — A  Dictionary  of  Dyeing  and  Calico  Printing: 

Containing  a  brief  account  of  all  the  Substances  and  Processes  in 
use  in  the  Art  of  Dyeing  and  Printing  Textile  Fabrics  ;  with  Practical 
Receipts  and  Scientific  Information.  By  CHARLES  O'NEILL,  Analy- 
tical Chemist.  To  which  is  added  an  Essay  on  Coal  Tar  Colors  and 
their  application  to  Dyeing  and  Calico  Printing.  By  A.  A.  FESQUET, 
Chemist  and  Engineer.  With  an  appendix  on  Dyeing  and  Calico 
Printing,  as  shown  at  the  Universal  Exposition,  Paris,  1867-  8vo., 
491  pages |3.50 

ORTON. — Underground  Treasures'. 

How  and  Where  to  Find  Them.  A  Key  for  the  Ready  Determination 
of  all  the  Useful  Minerals  within  the  United  States.  By  JAMES 
ORTON,  A.M.,  Late  Professor  of  Natural  History  in  Vassar  College^ 
/«J.  Y.;  Cor.  Mem.  of  the  Academy  of  Natural  Sciences,  Philadelphia, 
and  of  the  Lyceum  of  Natural  History,  New  York ;  author  of  the 
"  Andes  and  the  Amazon,"  etc.  A  New  Edition,  with  Additions. 
Illustrated  * -^ 


HENRY  CAREY  BAiRD   &   CO.'S   CATALOGUE.       21 


OSBORN.— The  Prospector's  Field  Book  and  Guide: 

In  the  Search  for  and  the  Easy  Determination  of  Ores  and  Other 
Useful  Minerals.  By  Prof.  H.  S.  OSBORN,  LL.  D.,  Author  of 
"The  Metallurgy  of  Iron  and  Steel;"  "A  Practical  Manual  of 
Minerals,  Mines,  and  Mining."  Illustrated  by  44  Engravings. 
I2mo $1.50 

OSBORN. — A  Practical  Manual  of  Minerals,  Mines  and  Min- 
ing: 

Comprising  the  Physical  Properties,  Geologic  Positions,  Local  Occur- 
rence and  Associations  of  the  Useful  Minerals;  their  Methods  of 
Chemical  Analysis  and  Assay :  together  with  Various  Systems  of 
Excavating  and  Timbering,  Brick  and  Masonry  Work,  during  Driv- 
ing, Lining,  Bracing  and  other  Operations,  etc.  By  Prof.  H.  S. 
OSBORN,  LL.  D.,  Author  of  the  "  Metallurgy  of  Iron  and  Steel." 
Illustrated  by  171  engravings  from  original  drawings.  8vo.  $4.50 

OVERMAN. — Thti  Manufacture  of  Steel : 

Containing  the  Practice  and  Principles  of  Working  and  Making  Steel. 
A  Handbook  for  Blacksmiths  and  Workers  in  Steel  and  Iron,  Wagon 
Makers,  Die  Sinkers,  Cutlers,  and  Manufacturers  of  Files  and  Hard- 
ware, of  Steel  and  Iron,  and  for  Men  of  Science  and  Art.  By 
FREDERICK  OVERMAN,  Mining  Engineer,  Author  of  the  "  Manu- 
facture of  lion,"  etc.  A  new,  enlarged,  and  revised  Edition.  By 
A.  A.  FESQUET,  Chemist  and  Engineer.  I2mo.  .  .  $1.50 

OVERMAN. — The  Moulder's  and  Founder's  Pocket  Guide  : 
A  Treatise  or*  Moulding  and  Founding  in  Green-sand,  Dry-sand,  Loam, 
and  Cement;  the  Moulding  of  Machine  Frames,  Mill-gear,  Hollow* 
ware,  Ornaments,  Trinkets,  Bells,  and  Statues ;  Description  of  Moulds 
for  Iron,  Bronze,  Brass,  and  other  Metals ;  Plaster  of  Paris,  Sulphur, 
Wax,  etc. ;  the  Construction  of  Melting  Furnaces,  the  Melting  and 
Founding  of  Metals ;  the  Composition  of  Alloys  and  their  Nature, 
etc.,  etc.  By  FREDERICK  OVERMAN,  M.  E.  A  new  Edition,  to 
which  is  added  a  Supplement  on  Statuary  and  Ornamental  Moulding, 
Ordnance,  Malleable  Iron  Castings,  etc.  By  A.  A.  FESQUET,  Chem- 
ist and  Engineer.  Illustrated  by  44  engravings.  I2mo.  .  $2.OQ 

PAINTER,  GILDER,  AND  VARNISHER'S  COMPANIONS 
Containing  Rules  and  Regulations  in  everything  relating  to  the  AriS 
of  Painting,  Gilding,  Varnishing,  Glass-Staining,  Graining,  Marbling, 
Sign- Writing,  Gilding  on  Glass,  and  Coach  Painting  and  Varnishing; 
Tests  for  the  Detection  of  Adulterations  in  Oils,  Colors,  etc. ;  and  a 
Statement  of  the  Diseases  to  which  Painters  are  peculiarly  liable,  with 
the  Simplest  and  Best  Remedies.  Sixteenth  Edition.  Revised,  with 
an  Appendix.  Containing  Colors  and  Coloring — Theoretical  and 
Practical.  Comprising  descriptions  of  a  great  variety  of  Additional 
Pigments,  their  Qualities  and  Uses,  to  which  are  added,  Dryers,  and 
Modes  and  Operations  of  Painting,  etc.  Together  with  ChevreuFs 
Principles  of  Harmony  and  Contrast  of  Colors.  I2mo.  Cloth  $1.50 

5PALLETT.— The  Miller's,  Millwright's,  and  Engineer's  Guide. 

:    By  HKNRY  PALLETT.     Illustrated.     I2mo.       .        .       •        $2.00 


22          HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

PERCY. — The  Manufacture  of  Russian  Sheet-Iron. 

By  JOHN  PERCY,  M.  D.,  F.  R.  S.,  Lecturer  on  Metallurgy  at  tht 
Royal  School  of  Mines,  and  to  The  Advance  Class  of  Artillery 
Officers  at  the  Royal  Artillery  Institution,  Woolwich;  Author  of 
"  Metallurgy."  With  Illustrations.  8vo.,  paper  .  .  50  cts. 

PERKINS.— Gas  and  Ventilation  : 

Practical  Treatise  on  Gas  and  Ventilation.  With  Special  Relation 
to  Illuminating,  Heating,  and  Cooking  by  Gas.  Including  Scientific 
Helps  to  Engineer-students  and  others.  With  Illustrated  Diagrams, 
By  E.  E.  PERKINS.  I2mo.,  cloth $1.25 

PERKINS  AND  STOWE.— A  New  Guide  to  the  Sheet-iron 

and  Boiler  Plate  Roller : 

Containing  a  Series  of  Tables  showing  the  Weight  of  Slabs  and  Pile* 
to  Produce  Boiler  Plates,  and  of  the  Weight  of  Piles  and  the  Sizes  of 
Bars  to  produce  Sheet-iron;  the  Thickness  of  the  Bar  Gauga 
in  decimals ;  the  Weight  per  foot,  and  the  Thickness  on  the  Bar  or 
Wire  Gauge  of  the  fractional  parts  of  an  inch;  the  Weight  per 
sheet,  and  the  Thickness  on  the  Wire  Gauge  of  Sheet-iron  of  various 
dimensions  to  weigh  112  ibs.  per  bundle;  and  the  conversion  of 
Short  Weight  into  Long  Weight,  and  Long  Weight  into  Short. 
Estimated  and  collected  by  G.  H.  PERKINS  and  J.  G.  STOWE.  $2.50 

POWELI CHANCE— HARRISc— The    Principles  of  Glass 

Making. 

By  HARRY  J.  POWELL,  B.  A.  Together  with  Treatises  on  Crown  and 
Sheet  Glass;  by  HENRY  CHANCE,  M.  A.  And  Plate  Glass,  by  H. 
G.  HARRIS,  Asso.  M.  Inst.  C.  E.  Illustrated  i8mo.  .  $1.50 

PROCTOR.— A  Pocket-Book  of  Useful  Tables  and  Formulae 

for  Marine  Engineers  : 

By  FRANK  PROCTOR.  Second  Edition,  Revised  and  Enlarged. 
Full -bound  pocket-book  form $1.50 

REGNAULT.— Elements  of  Chemistry: 

By  M.  V.  REGNAULT.  Translated  from  the  French  by  T.  FORREST 
BETTON,  M.  D.,  and  edited,  with  Notes,  by  JAMES  C.  BOOTH,  Melter 
and  Refiner  U.  S.  Mint,  and  WILLIAM  L.  FABER,  Metallurgist  and 
Mining  Engineer.  Illustrated  by  nearly  700  wood-engravings.  Com- 
prising nearly  1,500  pages.  In  two  volumes,  8vo.,  cloth  .  $7.50 

RICHARDS.— Aluminium  : 

Its  History,  Occurrence,  Properties,  Metallurgy  and  Applications, 
including  its  Alloys.  By  JOSEPH  W.  RICHARDS,  A.  C.,  Chemist  and 
Practical  Metallurgist,  Member  of  the  Deutsche  Chemische  Gesell- 
schaft.  Illustrated $5 .00 

RIFFAULT,  VERGNAUD,  and  TOUSSAINT.— A  Practical 

Treatise  on  the  Manufacture  of  Colors  for  Painting : 
Comprising  the  Origin,  Definition,  and  Classification  of  Colors;  the 
Treatment  of  the  Raw  Materials ;  the  best  Formulae  and  the  Newest 
Processes  for  the  Preparation  of  every  description  of  Pigment,  and 
the  Necessary  Apparatus  and  Directions  for  its  Use ;  Dryers ;  tho 
Testing.  Application,  and  Qualities  of  Paints,  etc.,  etc.  By  MM. 
RIFFAULT,  VERGNAUD,  and  TOUSSAINT.  Revised  and  Edited  by  M. 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          23 

F.  MALEPEYRE.  Translated  from  the  French,  by  A.  A.  FESQUW; 
Chemist  and  Engineer.  Illustrated  by  Eighty  engravings.  In  one 
vol.,  8vo.,  659  pages •  •  $7-S& 

ROPER. — A  Catechism  of  High-Pressure,  or  Non- Condensing. 

Steam -Engines : 

Including  the  Modelling,  Constructing,  and  Management  of  Steam* 
Engines  and  Steam  Boilers.  With  valuable  illustrations.  By  STE- 
PHEN ROPER,  Engineer.  Sixteenth  edition,  revised  and  enlarged. 
i8mo.,  tucks,  gilt  edge $2.OQ 

ROPER. — Engineer's  Handy-Book: 

Containing  a  full  Explanation  of  the  Steam-Engine  Indicator,  and  its 
Use  and  Advantages  to  Engineers  and  Steam  Users.  With  Formula 
for  Estimating  the  Power  of  all  Classes  of  Steam-Engines ;  also, 
Facts,  Figures,  Questions,  and  Tables  for  Engineers  who  wish  to 
qualify  themselves  for  the  United  States  Navy,  the  Revenue  Service, 
the  Mercantile  Marine,  or  to  take  charge  of  the  Better  Class  of  Sta- 
tionary Steam-Engines.  Sixth  edition.  i6mo.,  690  pages,  tucks, 
gilt  edge .  #3.50 

ROPER. — Hand-Book  of  Land  and  Marine  Engines  : 
Including  the  Modelling,  Construction,  Running,  and  Management 
of  Lane1  and  Marine  Engines  and  Boilers.     With  illustrations.     By 
STEPHEN  ROPER,  Engineer.    Sixth  edition.     I2mo.,tvcks,  gilt  edge. 

#3-50 
ROPER.— Hand-Book  of  the  Locomotive  : 

Including  the  Construction  of  Engines  and  Boilers,  and  the  Construc- 
tion, Management,  and  Running  of  Locomotives.  By  STEPHEN 
ROPER.  Eleventh  edition.  i8mo.,  tucks,  gilt  edge  .  $2.50 

ROPER. — Hand-Book  of  Modern  Steam  Fire-Engines. 

With  illustrations.  By  STEPHEN  ROPER,  Engineer.  Fourth  edition, 
I2mo.,  tucks,  gilt  edge $3-S° 

ROPER. — Questions  and  Answers  for  Engineers. 

This  little  book  contains  all  the  Questions  that  Engineers  will  be 
asked  when  undergoing  an  Examination  for  the  purpose  of  procuring 
Licenses,  and  they  are  so  plain  that  any  Engineer  or  Fireman  of  or 
dinary  intelligence  may  commit  them  to  memory  in  a  short  time.  By 
STEPHEN  ROPER,  Engineer.  Third  edition  .  .  .  $3.00 

HOPER. — Use  and  Abuse  of  the  Steam  Boiler. 
By  STEPHEN  ROPER,  Engineer.     Eighth  edition,  with  illustrations. 
l8mo.,  tucks,  gilt  edge $2.00 

ROSE. — The  Complete  Practical  Machinist : 

Embracing  Lathe  Work,  Vise  Work,  Drills  and  Drilling,  Taps  and 
Dies,  Hardening  and  Tempering,  the  Making  and  Use  of  Tools, 
Tool  Grinding,  Marking  out  Work,  etc.  By  JOSHUA  ROSE.  Illus* 
trated  by  356  engravings.  Thirteenth  edition,  thoroughly  revise<f 
and  in  great  part  rewritten.  In  one  vol.,  121110.,  439  pages  #2.50- 

ROSE. — Mechanical  Drawing  Self- Taught: 

Comprising  Instructions  in  the  Selection  and  Preparation  of  Drawing 
Instruments,  Elementary  Instruction  in  Practical  Mechanical  Draw 


24         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

mgi  together  with  Examples  in  Simple  Geometry  and  Elementary 
Mechanism,  including  Screw  Threads,  Gear  Wheels,  Mechanical 
Motions,  Engines  and  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  330  engravings.  8vo.,  313  pages  ....  #4.00 

ROSE.— The  Slide- Valve  Practically  Explained: 

Embracing  simple  and  complete  Practical  Demonstrations  of  th, 
operation  of  each  element  in  a  Slide-valve  Movement,  and  illustrat- 
ing the  effects  of  Variations  in  their  Proportions  by  examples  care- 
fully selected  from  the  most  recent  and  successful  practice.  By 
JOSHUA  ROSE,  M.  E.  Illustrated  by  35  engravings  .  $1.00 

ROSS. — The  Blowpipe  in  Chemistry,  Mineralogy  and  Geology: 
Containing  all  Known  Methods  of  Anhydrous  Analysis,  many  Work- 
ing Examples,  and  Instructions  for  Making  Apparatus.  By  LIEUT.- 
COLONEL  W.  A.  Ross,  R.  A.,  F.  G.  S.  With  120  Illustrations. 
I2mo #2.00 

SHAW.— Civil  Architecture : 

Being  a  Complete  Theoretical  and  Practical  System  of  Building,  con- 
taining  the  Fundamental  Principles  of  the  Art.  By  EDWARD  SHAW, 
Architect.  To  which  is  added  a  Treatise  on  Gothic  Architecture,  etc. 
By  THOMAS  W.  SILLOWAY  and  GEORGE  M.  HARDING,  Architects. 
The  whole  illustrated  by  102  quarto  plates  finely  engraved  on  copper. 
Eleventh  edition.  4to $10.00 

SHUNK. — A  Practical  Treatise  on  Railway  Curves  and  Loca- 
tion, for  Young  Engineers. 
By  W.  F.  SHUNK,  C.  E.    I2mo.    Full  bound  pocket-book  form  $2.00 

SLATER. — The  Manual  of  Colors  and  Dye  Wares. 
By  J.  W.  SLATER.     i2mo #3-oo 

SLOAN. — American  Houses  : 

A  variety  of  Original  Designs  for  Rural  Buildings.  Illustrated  by 
26  colored  engravings,  with  descriptive  references.  By  SAMUEL 
SLOAN,  Architect.  8vo.  ., $1.50 

6LOAN. — Homestead  Architecture : 

Containing  Forty  Designs  for  Villas,  Cottages,  and  Farm-houses,  with 
Essays  on  Style,  Construction,  Landscape  Gardening,  Furniture,  etc., 
etc.  Illustrated  by  upwards  of  200  engravings.  By  SAMUEL  SLOAN, 
Architect.  8vo $3. 50 

SLOANE. — Hoi7>e  Experiments  in  Science. 
By  T.  O'CoNOR  SLCANE,  E.  M.,  A.  M.,  Fh.  D.     Illustrated  by  91 
engravings.     I2mo. $1.50 

SMEATON. — Builder's  Pockt^ Companion : 

Containing  the  Elements  of  Building,  Surveying,  and  Architecture ; 
with  Practical  Rules  and  Instructions  connected  with  the  subject. 

'    By  A.  C.  SMEATON,  Civil  Engineer,  etc.     I2mo.       .        .        $1.50 

SMITH. — A  Manual  of  Political  Economy. 
By  E.  PESHINE  SMITH.    A  New  Edition,  to  which  is  added  a  full 
Index.     I2mo $i  25 


HENRY  CAREY  EAIRD  &  CO.'S  CATALOGUE.         25 

SMITH. — Parks  and  Pleasure  -  Grounds : 

Or  Practical  Notes  on  Country  Residences,  Villas,  Public  Parks,  and 
Gardens.  By  CHARLES  H.  J.  SMITH,  Landscape  Gardener  and 
Garden  Architect,  etc.,  etc.  I2mo.  ....  $2.00 

SMITH.— The  Dyer's  Instructor: 

Comprising  Practical  Instructions  in  the  Art  of  Dyeing  Silk,  Cotton, 
Wool,  and  Worsted,  and  Woolen  Goods ;  containing  nearly  800 
Receipts.  To  which  is  added  a  Treatise  on  the  Art  of  Padding;  ancj 
the  Printing  of  Silk  Warps,  Skeins,  and  Handkerchiefs,  and  th« 
various  Mordants  and  Colors  for  the  different  styles  of  such  work.- 
By  DAVID  SMITH,  Pattern  Dyer.  I2mo.  .  .  .  $2.00 

SMYTH. — A  Rudimentary  Treatise  on  Coal  and  Coal- Mining. 
By  WARRINGTON  W.  SMYTH,  M.  A.,  F.  R.  G.,  President  R.  G.  S, 
of  Cornwall.  Fifth  edition,  revised  and  corrected.  With  numer- 
ous illustrations.  I2mo.  #l«75 

SNIVELY.— Tables  for  Systematic  Qualitative  Chemical  AnaK 

ysis. 
By  JOHN  H.  SNIVELY,  Phr.  D.     8vo.        .        .        .        .        $1.00 

SNIVELY. — The  Elements  of  Systematic  Qualitative  Chemical 

Analysis : 

A  Hand-book  for  Beginners.    By  JOHN  H.  SNIVELY,  Phr.  D.    i6mo. 

$2.00 

STOKES.— The  Cabinet- Maker  and  Upholsterer's  Companion  : 
Comprising  the  Art  of  Drawing,  as  applicable  to  Cabinet  Work; 
Veneering,  Inlaying,  and  Buhl- Work ;  the  Art  of  Dyeing  and  Stain- 
ing Wood,  Ivory,  Bone,  Tortoise-Shell,  etc.  Directions  for  Lacker- 
ing, Japanning,  and  Varnishing;  to  make  French  Polish,  Glues, 
Cements,  and  Compos-la' ns;  with  numerous  Receipts,  useful  to  work 
men  generally.  Bv  STOKES.  Illustrated.  A  New  Edition,  with 
an  Appendix  upor  vench  Polishing,  Staining,  Imitating,  Varnishing, 
etc.,  etc.  I2mo $1.25 

STRENGTH  AND  OTHER  PROPERTIES  OF  METALS^: 
Reports  of  Experiments  on  the  Strength  and  other  Properties  of 
Metals  for  Cannon.  With  a  Description  of  the  Machines  for  Testing 
Metals,  and  of  the  Classification  of  Cannon  in  service.  By  Officers 
of  the  Ordnance  Department,  U.  S.  Army.  By  authority  of  the  Secrc. 
taryofWar.  Illustrated  by  25  large  steel  plates.  Quarto  .  $10.00 

SULLIVAN. — Protection  to  Native  Industry. 
By  Sir  EDWARD  SULLIVAN,  Baronet,  author  of  "  Ten  Chapters  en 
Social  Reforms."     8vo £1.00 

SULZ. — A  Treatise  on  Beverages : 

Or  the  Complete  Practical  Bottler.  Full  instructions  for  Laboratory 
Work,  with  Original  Practical  Recipes  for  all  kinds  of  Carbonated 
Drinks,  Mineral  Waters,  Flavorings,  Extracts,  Syrups,  etc.  By 
CHAS.  HERMAN  SULZ,  Technical  Chemist  and  Practical  Bottler. 
Illustrated  by  428  Engravings.  818  pp.  Jivo.  .  .  $10.00 


26         HENRY  CAREY  BAIRt?  &  CO.'S  CATALOGUE. 


BYME. — Outlines  of  an  Industrial  Science. 

By  DAVID  SYME.     I2mo.  .  .  j$2.ot 

TABLES     SHOWING     THE     WEIGHT     OF     ROUND, 

SQUARE,  AND  FLAT  BAR  IRON,  STEEL,  ETC., 
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TAYLOR. — Statistics  of  Coal : 

Including  Mineral  Bituminous  Substances  employed  in  Arts  and 
Manufactures;  with  their  Geographical,  Geological,  and  Commercial 
Distribution  and  Amount  of  Production  and  Consumption  on  the 
American  Continent.  With  Incidental  Statistics  of  the  Iron  Manu- 
facture. By  R.  C.  TAYLOR.  Second  edition,  revised  by  S.  S.  HALDE* 
MAN.  Illustrated  by  five  Maps  and  many  wood  engravings.  8vo., 
cloth $10.00 

TEMPLETON. — The  Practical  Examinator  on  Steam  and  the 

Steam -Engine : 

With  Instructive  References  relative  thereto,  arranged  for  the  Use  of 
Engineers,  Students,  and  others.  By  WILLIAM  TEMPLETON,  En. 
gineer.  I2mo.  ........  $1.00 

THAUSING.—  The  Theory  and  Practice  of  the  Preparation  of 

Malt  and  the  Fabrication  of  Beer : 

With  especial  reference  to  the  Vienna  Process  of  Brewing.  Elab- 
orated from  personal  experience  by  JULIUS  E.  THAUSING,  Professor 
at  the  School  for  Brewers,  and  at  the  Agricultural  Institute,  Modling, 
near  Vienna.  Translated  from  the  German  by  WILLIAM  T.  BRANNT, 
Thoroughly  and  elaborately  edited,  with  much  American  matter,  and 
according  to  the  latest  and  most  Scientific  Practice,  by  A.  SCHWAKZ 
and  DR.  A.  H.  BAUER.  Illustrated  by  140  Engravings.  8vo.,  815 
pages  .  .  .  .  .  .  ...  .  .  $10.00 

THOMAS.— The  Modern  Practice  of  Photography: 
By  R.  W.  THOMAS,  F.  C.  S.    8vo.  ....  25 

THOMPSON. — Political  Economy.     With  Especial  Reference 

to  the  Industrial  History  of  Nations  : 

By  ROBERT  E.  THOMPSON,  M.  A.,  Professor  of  Social  Science  in  the 
University  of  Pennsylvania.  I2mo.  ....  $1.50 

THOMSON. — Freight  Charges  Calculator: 

By  ANDREW  THOMSON,  Freight  Agent.     2*jmo.        .        .        $1.25 

TURNER'S  (THE)  COMPANION: 

Containing  Instructions  in  Concentric,  Elliptic,  and  Eccentric  Turn, 
ing;  also  various  Plates  of  Chucks,  Tools,  and  Instruments;  and 
Directions  for  using  the  Eccentric  Cutter,  Drill,  Vertical  Cutter,  and 
Circular  Rest;  with  Patterns  and  Instructions  for  working  them. 
I2mo $1.25 

TURNING :   Specimens  of  Fancy  Turning  Executed  on  the 

Hand  or  Foot- Lathe : 

With  Geometric,  Oval,  and  Eccentric  Chucks,  and  Elliptical  Cutting 
Frame.  By  an  Amateur.  Illustrated  by  30  exquisite  Photographs. 
4*o. $3.00 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          27 

VAILE. — Galvanized- Iron  Cornice-Worker's  Manual: 
Containing  Instructions  in  Laying  out  the  Different  Mitres,  and 
Making  Patterns  for  all  kinds  of  Plain  and  Circular  Work.  Also, 
Tables  of  Weights,  Areas  and  Circumferences  of  Circles,  and  other 
Matter  calculated  to  Benefit  the  Trade.  By  CHARLES  A.  VAILE. 
Illustrated  by  twenty-one  plates.  4to.  ....  $5 .00 

VILLE. — On  Artificial  Manures  : 

Their  Chemical  Selection  and  Scientific  Application  to  Agriculture. 
A  series  of  Lectures  given  at  the  Experimental  Farm  at  Vincennes, 
during  1867  and  1874-75.  By  M.  GEORGES  VILLE.  Translated  and 
Edited  by  WILLIAM  CROOKES,  F.  R.  S.  Illustrated  by  thirty-one 
engravings.  8vo.,  450  pages $6.00 

VILLE. — The  School  of  Chemical  Manures  : 
Or,  Elementary  Principles  in  the  Use  of  Fertilizing  Agents.     From 
the  French  of  M.  GEO.  VILLE,  by  A.  A.  FESQUET,  Chemist  and  En- 
gineer.    With  Illustrations.     I2mo.  .         .         .         .         $1.2$ 

VOQDES. — The  Architect's  and  Builder's  Pocket- Companion 

and  Price-Book : 

Consisting  of  a  Shoit  but  Comprehensive  Epitome  of  Decimals,  Duo- 
decimals, Geometry  and  Mensuration  ;  with  Tables  of  United  States 
Measures,  Sizes,  Weights,  Strengths,  etc.,  of  Iron,  Wood,  Stone, 
.Brick,  Cement  and  Concretes,  Quantities  of  Materials  in  given  Sizes 
and  Dimensions  of  Wood,  Brick  and  Stone;  and  full  and  complete 
Bills  of  Prices  for  Carpenter's  Work  and  Painting;  also,  Rules  for 
Computing  and  Valuing  Brick  and  Brick  Work,  Stone  Work,  Paint- ' 
ing,  Plastering,  with  a  Vocabulary  of  Technical  Terms,  etc.  By 
FRANK  W.  VOGDES,  Architect,  Indianapolis,  Ind.  Enlarged,  revised, 
and  corrected.  In  one  volume,  368  pages,  full-bound,  pocket-book 

form,  gilt  edges £2.00 

Cloth         .  l.SQ 

VAN  CLEVE. — The  English  and  American  Mechanic : 

Comprising  a  Collection  of  Over  Three  Thousand  Receipts,  Rules, 
and  Tables,  designed  for  the  Use  of  every  Mechanic  and  Manufac- 
turer. By  B.  FRANK  VAN  CLEVE.  Illustrated.  500  pp.  I2mo.  $2.00 

WAHNSCHAFFE. — A  Guide  to  the  Scientific  Examination 

of  Soils: 

Comprising  Select  Methods  of  Mechanical  and  Chemical  Analysis 
and  Physical  Investigation.  Translated  from  the  German  of  Dr.  F. 
WAHNSCHAFFE.  With  additions  by  WILLIAM  T.  BRANNT.  Illus- 
trated by  25  engravings.  I2mo.  177  pages  .  .  .  #1.50 

WALL. — Practical  Graining : 

With  Descriptions  of  Colors  Employed  and  Tools  Used.  Illustrated 
by  47  Colored  Plates,  Representing  the  Various  Woods  Used  E 
Interior  Finishing.  By  WILLIAM  E.  WALL.  8vo.  .  $2.5? 

WALTON.— Coal-Mining  Described  and  Illustrated: 

By  THOMAS  H.  WALTON,  Mining  Engineer.  Illustrated  by  24  large 
and  elaborate  Plates,  after  Actual  Workings  and  Apparatus.  $5.00, 


28         HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE. 

WARE.—  The  Sugar  Beet. 

Including  a  History  of  the  Beet  Sugar  Industry  in  Europe,  Varietiei 
of  the  Sugar  Sect,  Examination,  Soils,  Tillage,  Seeds  and  Sowing^ 
Yield  and  Cost  of  Cultivation,  Harvesting,  Transportation,  Conserve 
tion,  Feeding  Qualities  of  the  Beet  and  of  the  Pulp,  etc.  By  LEWII 
S.  WARE,  C.  E.,  M.  E.  Illustrated  by  ninety  engravings.  8vo. 


WARN.—  The  Sheet-Metal  Worker's  Instructor: 

For  Zinc,  Sheet-Iron,  Copper,  and  Tin-Plate  Workers,  etc.  Contain- 
ing  a  selection  of  Geometrical  Problems  ;  also,  Practical  and  Simple 
Rules  for  Describing  the  various  Patterns  required  in  the  different 
branches  of  the  above  Trades.  By  REUBEN  H.  WARN,  Practical 
Tin-Plate  Worker.  To  which  is  added  an  Appendix,  containing 
Instructions  for  Boiler-Making,  Mensuration  of  Surfaces  and  Solids, 
Rules  for  Calculating  the  Weights  of  different  Figures  of  Iron  and 
Steel,  Tables  of  the  Weights  of  Iron,  Steel,  etc.  Illustrated  by  thirty- 
two  Plates  and  thirty-seven  Wood  Engravings.  8vo.  .  $3.00 

WARNER.  —  New  Theorems,  Tables,  and  Diagrams,  for  the 
Computation  of  Earth-work  : 

Designed  for  the  use  of  Engineers  in  Preliminary  and  Final  Estimates, 
of  Students  in  Engineering,  and  of  Contractors  and  other  non-profesi 
sional  Computers.  In  two  parts,  with  an  Appendix.  Part  I.  A  Prac- 
tical Treatise;  Part  II.  A  Theoretical  Treatise,  and  the  Appendix, 
,  Containing  Notes  to  the  Rules  and  Examples  of  Part  I.  ;  Explana- 
tions of  the  Construction  of  Scales,  Tables,  and  Diagrams,  and  a 
Treatise  upon  Equivalent  Square  Bases  and  Equivalent  Level  Heights. 
The  whole  illustrated  by  numerous  original  engravings,  comprising 
explanatory  cuts  for  Definitions  and  Problems,  Stereometric  Scales 
and  Diagrams,  and  a  series  of  Lithographic  Drawings  from  Models  i 
Showing  all  the  Combinations  of  Solid  Forms  which  occur  in  Railroad 
Excavations  and  Embankments.  By  JOHN  WARNER,  A.  M.,  Mining 
and  Mechanical  Engineer.  Illustrated  by  14  Plates.  A  new,  revised 
and  improved  edition.  8vo.  ......  $4.00 

WATSON.—  A  Manual  of  the  Hand-Lathe  : 

Comprising  Concise  Directions  for  Working  Metals  of  all  kinds, 
Ivory,  Bone  and  Precious  Woods;  Dyeing,  Coloring,  and  French 
Polishing;  Inlaying  by  Veneers,  and  various  methods  practised  to 
produce  Elaborate  work  with  Dispatch,  and  at  Small  Expense.  By 
EGBERT  P.  WATSON,  Author  of  "  The  Modern  Practice  of  American 
Machinists  and  Engineers."  Illustrated  by  78  engravings.  $1.50 

WATSON.—  The  Modern  Practice  of  American  Machinists  and 

Engineers  : 

Including  the  Construction,  Application,  and  Use  of  Drills,  Lathe 
Tools,  Cutters  for  Boring  Cylinders,  and  Hollow-work  generally,  with 
the  most  Economical  Speed  for  the  same  ;  the  Results  verified  by 
Actual  Practice  at  the  Lathe,  the  Vise,  and  on  the  Floor.  Together 


HENRY  CAREY  BAIRD  &  CO.'S  CATALOGUE.          29 

with  Work*top  Management,  Economy  of  Manufacture,  the  Steam 

Engine,  Boilers,  Gears,  Belting,  etc.,  etc.     By  EGBERT  P.  WATSON, 

Illustrated  by  eighty-six  engravings.     I2mo.        .         .         .         jJte-50 

WATSON.— The  Theory  and  Practice  of  the  Art  of  Weaving 

by  Hand  and  Power  • 

With  Calculations  and  Tables  for  the  Use  of  those  connected  with  the 
Trade.  By  JOHN  WATSON,  Manufacturer  and  Practical  Machine- 
Maker.  Illustrated  by  large  Drawings  of  the  best  Power  Looms. 

8vo.  ...* .        $6.00 

, WATT.— The  Art  of  Soap  Making: 

A  Practical  Hand-book  of  the  Manufacture  of  Hard  and  Soft  Soaps, 
Toilet  Soaps,  etc.,  including  many  New  Processes,  and  a  Chapter  on 
the  Recovery  of  Glycerine  from  Waste  Leys.  By  ALEXANDER 

WATT.    111.     i2mo #3.00 

WEATHERLY.— Treatise  on  the  Art  of  Boiling  Sugar,  Crys- 
tallizing, Lozenge-making,  Comfits,  Gum  Goods, 
And  other  processes  for  Confectionery,  etc.,  in  which  are  explained. 
in  an  easy  and  familiar  manner,  the  various  Methods  of  Manufacture 
i»g  every  Description  of  Raw  and  Refined  Sugar  Goods,  as  aold  by 

Confectioners  and  others.     I2mo $I«5° 

WIGHTWICK.— Hints  to  Young  Architects: 
Comprising  Advice  to  those  who,  while  yet  at  school,  are  destined 
to  the  Profession ;  to  such  as,  having  passed  their  pupilage,  are  about 
to  travel ;  and  to  those  who,  having  completed  their  education,  are 
about  to  practise.  Together  with  a  Model  Specification  involving  a 
great  variety  of  instructive  and  suggestive  matter.  By  GEORGB 
WIGHTWICK,  Architect.  A  new  edition,  revised  and  considerably 
enlarged;  comprising  Treatises  on  the  Principles  of  Construction 
and  Design.  By  G.  HUSKISSON  GUILLAUME,  Architect.  Numerous 

Illustrations.     One  vol.  I2mo #2.00 

WILL. — Tables  of  Qualitative  Chemical  Analysis. 

With  an  Introductory  Chapter  on  the  Course  of  Analysis.  By  Pro- 
fessor HEINRICH  WILL,  of  Giessen,  Germany.  Third  American, 
from  the  eleventh  German  edition.  Edited  by  CHARLES  F.  HIMES, 
Ph.  D.,  Professor  of  Natural  Science,  Dickinson  College,  Carlisle,  Pa- 

8vo.     '       .  #1-50 

WILLIAMS.— On  Heat  and  Steam : 

Embracing  New  Views  of  Vaporization,  Condensation,  and  ExpV> 
sion.  By  CHARLES  WYE  WILLIAMS,  A.  I.  C.  E.  Illustrated  8vo. 

$2.50 
WILSON. — A  Treatise  on  Steam  Boilers  : 

Their  Strength,  Construction,  and  Economical  Working.    By  RoBERt 

WILSON.     Illustrated  I2mo #2.50 

WILSON.— First  Principles  of  Political  Economy: 

With  Reference  to  Statesmanship  and  the  Progress  of  Civilization, 
tty  Professor  W.  D.  WILSON,  of  the  Cornell  University.  A  new  and 
revised  edition.  I2mo.  .  .  .  ,  .  .  .  $i-Sa 


30        HENRY   CAREY   BAIRD   &   CO.'S  CATALOGUE. 

WOHLER.— A  Hand-Bookof  Mineral  Analysis: 

By  F.  WOHLER,  Professor  of  Chemistry  in  the  University  of  GSttin- 
gen.  Edited  by  HENRY  B.  NASON,  Professor  of  Chemistry  in  the 
Renssalaer  Polytechnic  Institute,  Troy,  New  York.  Illustrated. 

I2mo.         .  *•?  en 

•          .          pz.^u 

WORSSAM.— On  Mechanical  Saws  : 

From  the  Transactions  of  the  Society  of  Engineers,  1869.  By  S.  W. 
WORSSAM,  JR.  Illustrated  by  eighteen  large  plates.  8vo.  #2.50 


RECENT   ADDITIONS. 

BRANNT. — Varnishes,  Lacquers,  Printing  Inks,  and  Sealing 

Waxes : 

Their  Raw  Materials  and  their  Manufacture.  39  Illustrations. 
I2mo.  338  pages. $3.00 

BRANNT— The  Practical  Scourer  and  Garment  Dyer: 

Comprising  Dry  or  Chemical  Cleaning ;  the  Art  of  Removing  Stains ; 
Fine  Washing ;  Bleaching  and  Dyeing  of  Straw  Hats,  Gloves,  and 
Feathers  of  all  kinds;  Dyeing  of  Worn  Clothes  of  all  fabrics,  in- 
cluding Mixed  Goods,  by  One  Dip;  and  the  Manufacture  of  Soaps 
and  Fluids  for  Cleansing  Purposes.  Edited  by  WILLIAM  T.  BRANNT, 
Editor  of  "The  Techno-Chemical  Receipt  Book."  Illustrated. 
203  pages.  I2mo. $2.00 

BRANNT.— The  Metallic  Alloys : 

A  Practical  Guide  for  the  Manufacture  of  all  kinds  of  Alloys,  Amal- 
gams and  Solders  used  by  Metal  Workers,  especially  by  Bell  Founders, 
Bronze  Workers,  Tinsmiths,  Gold  and  Silver  Workers,  Dentists,  etc., 
etc.,  as  well  as  their  Chemical  and  Physical  Properties.  Edited 
chiefly  from  the  German  of  A.  Krupp  and  Andreas  Wildberger,  with 
additions  by  WM.  T.  BRANNT.  Illustrated.  I2mo.  $3.00 

BRANNT. — A  Practical  Treatise  on  the  Manufacture  of  Vine- 
gar and  Acetates,  Cider,  and  Fruit- Wines : 
Preservation  of  Fruits  and  Vegetables  by  Canning  and  Evaporation ; 
Preparation  of  Fruit-Butters,  Jellies,  Marmalades,  Catchups,  Pickles, 
Mustards,  etc.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated  by  79  Engravings.  479  pp.  8vo.  $5.00 

BRANNT.— The  Metal  Worker's    Handy-Book   of  Receipts 

and  Processes : 

Being  a  Collection  of  Chemical  Formulas  and  Practical  Manipula- 
tions for  the  working  of  all  Metals;  including  the  Decoration  and 
Beautifying  of  Articles  Manufactured  therefrom,  as  well  as  their 
Preservation.  Edited  from  various  sources.  By  WILLIAM  T. 
BRANNT.  Illustrated.  iamo.  $2.50 


HENRY   CAREY  BAIRD   &   CO.'S  CATALOGUE.       3I 

DEITE.— A  Practical  Treatise   on   the  Manufacture  of  Per- 
fumery : 

Comprising  directions  for  making  all  kinds  of  Perfumes,  Sachet 
Powders,  Fumigating  Materials,  Dentifrices,  Cosmetics,  etc.,  with  a 
full  account  of  the  Volatile  Oils,  Balsams,  Resins,  and  other  Natural 
and  Artificial  Perfume-substances,  including  the  Manufacture  of 
Fruit  Ethers,  and  tests  of  their  purity.  By  Dr.  C.  DEITE,  assisted 
by  L.  BORCHERT,  F.  EICHBAUM,  E.  KUGLER,  H.  TOEFFNER,  and 
other  experts.  From  the  German,  by  WM.  T.  BRANNT.  28  Engrav- 
ings. 358  pages.  8vo. $3.00 

EDWARDS. — American   Marine  Engineer,    Theoretical   and 

Practical : 

With  Examples  of  the  latest  and  most  approved  American  Practice. 
By  EMORY  EDWARDS.  85  illustrations.  12010.  .  .  $2.50 

EDWARDS. — 900    Examination   Questions  and   Answers  : 

For  Engineers  and  Firemen  (Land  and  Marine)  who  desire  to  ob- 
tain a  United  States  Government  or  State  License.  Pocket-book 

form,  gilt  edge        ,  .         .      . $1.5° 

POSSELT.— Technology  of  Textile  Design  : 

Being  a  Practical  Treatise  on  the  Construction  and  Application  of 
Weaves  for  all  Textile  Fabrics,  with  minute  reference  to  the  latest 
Inventions  for  Weaving.  Containing  also  an  Appendix,  showing 
the  Analysis  and  giving  the  Calculations  necessary  for  the  Manufac- 
tuie  of  the  various  Textile  Fabrics.  By  £.  A.  POSSELT,  Head 
Master  Textile  Department,  Pennsylvania  Museum  and  School  of 
Industrial  Art,  Philadelphia,  with  over  1000  illustrations.  293 
pages.  410.  . $5-°° 

POSSELT. — The  Jacquard  Machine  Analysed  and  Explained: 

With  an  Appendix  on  the  Preparation  of  Jacquard  Cards,  and 
Practical  Hints  to  Learners  of  Jacquard  Designing.  By  E.  A. 
POSSELT.  With  230  illustrations  and  numerous  diagrams.  127  pp. 
4to $3.00 

POSSELT.— The  Structure  of  Fibres,  Yarns  and  Fabrics : 
Being  a  Practical  Treatise  for  the  Use  of  all  Persons  Employed  in 
the  Manufacture  of  Textile  Fabrics,  containing  a  Description  of  the 
Growth  and  Manipulation  of  Cotton,  Wool,  Worsted,  Silk,  Flax, 
Jute,  Ramie,  China  Grass  and  Hemp,  and  Dealing  with  all  Manu- 
facturers' Calculations  for  Every  Class  of  Material,  also  Giving 
Minute  Details  for  the  Structure  of  all  kinds  of  Textile  Fabrics,  and 
an  Appendix  of  Arithmetic,  specially  adapted  for  Textile  Purposes. 
By  E.  A.  POSSELT.  Over  400  Illustrations,  quarto.  .  $10.00 

RICH. — Artistic  Horse-Shoeing: 

A  Practical  and  Scientific  Treatise,  giving  Improved  Methods  of 
Shoeing,  with  Special  Directions  for  Shaping  Shoes  to  Cure  Different 
Diseases  of  the  Foot,  and  for  the  Correction  of  Faulty  Action  in 
Trotters.  By  GEORGE  E.  RICH.  62  Illustrations.  153  pages. 
I2ino $1.00 


32       HENRY   CAREY   BAIRD  &  CO.'S  CATALOGUE. 

RICH ARDSON.— Practical  Blacksmithing : 

A  Collection  of  Articles  Contributed  at  Different  Times  by  Skilled 
Workmen  to  the  columns  of  "  The  Blacksmith  and  Wheelwright," 
and  Covering  nearly  the  Whole  Range  of  Blacksmithing,  from  the 
Simplest  Job  of  Work  to  some  of  the  Most  Complex  Forgings. 
Compiled  and  Edited  by  M.  T.  RICHARDSON. 

Vol.1.  210  Illustrations.  224  pages.  I2mo.  .  .  $1.00 
Vol.  II.  230  Illustrations.  262  pages.  I2mo.  .  .  $1.00 
Vol.  III.  390  Illustrations.  307  pages.  I2mo.  .  .  #1.00 
Vol.  IV.  226  Illustrations.  276  pages.  I2mo.  ,  .  $1.00 

RICHARDSON.— The  Practical  Horseshocr: 

Being  a  Collection  of  Articles  on  Horseshoeing  in  all  its  Branchet 
which  have  appeared  from  time  to  time  in  the  columns  of  "  1  he 
Blacksmith  and  Wheelwright,"  etc.  Compiled  and  edited  by  M,  T. 
RICHARDSON.  174  illustrations $1.00 

ROPER. — Instructions    and   Suggestions   for   Engineers  and 

Firemen : 
By  STEPHEN  ROPER,  Engineer.     i8mo.     Morocco        .        #2.00 

ROPER.— The  Steam  Boiler:  Its  Care  and  Management: 
By  STEPHEN  ROPER,  Engineer.     I2mo.,  tuck,  gilt  edges.         $2.00 

ROPER.— The  Young  Engineer's  Own  Book: 

Containing  an  Explanation  of  the  Principle  and  Theories  on  which 
the  Steam  Engine  as  a  Prime  Mover  is  Based.  By  STEPHEN  ROPER, 
Engineer.  160  illustrations,  363  pages.  i8mo.,  tuck  .  $3.00 

ROSE. — Modern  Steam -Engines: 

An  Elementary  Treatise  upon  the  Steam-Engine,  written  in  Plain 
language ;  for  Use  in  the  Workshop  as  well  as  in  the  Drawing  Office. 
Giving  Full  Explanations  of  the  Construction  of  Modern  Steam. 
Engines :  Including  Diagrams  showing  their  Actual  operation.  To- 
gether with  Complete  but  Simple  Explanations  of  the  operations  of 
Various  Kinds  of  Valves,  Valve  Motions,  and  Link  Motions,  etc., 
thereby  Enabling  the  Ordinary  Engineer  to  clearly  Understand  the 
Principles  Involved  in  their  Construction  and  Use,  and  to  Plot  out 
their  Movements  upon  the  Drawing  Board.  By  JOSHUA  ROSE.  M.  E. 
Illustrated  by  422  engravings.  Revised.  358  pp.  .  .  $6.00 

ROSE. — Steam  Boilers: 

A  Practical  Treatise  on  Boiler  Construction  and  Examination,  for  the 
Use  of  Practical  Boiler  Makers,  Boiler  Users,  and  Inspectors;  and 
embracing  in  plain  figures  all  the  calculations  necessary  in  Designing 
or  Classifying  Steam  Boilers.  By  JOSHUA  ROSE,  M.  E.  Illustrated 
by  73  engravings.  250  pages.  8vo $2.^0 

SCHRIBER.— The  Complete  Carriage  and  Wagon  Painter: 
A  Concise  Compendium  of  the  Art  of  Painting  Carriages,  Wagons, 
and  Sleighs,  embracing  Full  Directions  in  all  the  Various  Branches, 
including  Lettering,  Scrolling,  Ornamenting,  Striping,  Varnishing, 
and  Coloring,  with  numerous  Recipes  for  Mixing  Colors.  73  Illus- 
trations. 177  pp.  I2mo.  .  .  .  .  .  •  $1.00 


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